Bronchitis (Acute)

Bronchitis (Acute)

1 Overview

Summary and Quick Facts

  • Acute bronchitis is responsible for about 10 million annual doctor office visits in the United States. It is among the top 10 reasons people seek medical help. Acute bronchitis is an inflammation of the lining of the bronchial tubes characterized by cough with or without excessive mucus production.
  • Since acute bronchitis is frequently caused by viral infection, efforts should be made to prevent initial viral exposures from progressing into full-blown infection. Natural interventions are discussed within this protocol that may help alleviate symptoms or shorten illness duration.
  • The good news is that natural interventions such as Pelargonium sidosides and N-acetyl cysteine (NAC) may help ease the symptoms of acute bronchitis and make it go away faster.

Acute bronchitis—inflammation of the airways in the lungs—prompts about 10 million doctor’s office visits annually in the United States.

Most cases of acute bronchitis are caused by viral infections; bacterial infections cause very few cases.

The good news is that natural interventions such as Pelargonium sidosides and N-acetyl cysteine (NAC) may help ease the symptoms of acute bronchitis and make it go away faster.

Signs and Symptoms

  • productive cough persisting for 5 days or more
  • sore throat
  • wheezing
  • shortness of breath
  • fatigue
  • and low-grade fever

Causes and Risk Factors


  • Viruses, including rhinovirus, influenza virus, and some other common viruses
  • Less common causes include bacterial infections and environmental irritants

Risk Factors

  • Age (with very young and very old people being at higher risk for infections)
  • Vaccination – people who get vaccinated against influenza are less likely to get bronchitis
  • Working and living in crowded places

Diagnosis and Conventional Treatment


  • Based on clinical examination and symptoms
  • In some circumstances chest X-ray, sputum culture, or pulmonary functions tests may help differentiate acute bronchitis from other conditions.

Conventional Treatment

  • Refrain from intense activity
  • Drink lots of clear fluids (water)
  • Aspirin (for adults) or acetaminophen to treat fever

Note: Antibiotics are often hastily prescribed for acute bronchitis, which can result in the development of antibiotic resistance. This practice is ineffective because the vast majority of acute bronchitis cases in otherwise healthy adults are caused by viral infection for which antibiotics are not helpful.

Novel and Emerging Strategies

  • Procalcitonin (PCT) blood test. PCT testing may help minimize overzealous antibiotic prescribing.
  • Cimetidine. Cimetidine, an over-the-counter heartburn drug with intriguing immune-modulating properties, may support the immune response to viral infection.

Integrative Interventions

Note: In most cases, bronchitis represents a natural progression of the common cold or flu. Therefore, taking aggressive action at the first signs of the flu or common cold is one of the best ways to prevent progression to acute bronchitis. The following interventions should be used at the first signs of a cold or the flu. Readers should also review the Common Cold and Influenza protocols.

  • Zinc. Zinc has been shown to prevent viral replication, reduce histamine release, and inhibit the production of other inflammatory mediators.
  • Garlic. Garlic has demonstrated antiviral activity against rhinovirus and a variety of other pathogens.
  • Vitamin D. Vitamin D supplements, in doses ranging from 300 IU to 4000 IU daily, have been linked to a 19% reduction in risk of acute respiratory infection.
  • Melatonin. Melatonin helps combat many types of viral infections and is associated with an increased production of antibodies.

The following interventions have been studied in the context of bronchitis.

  • Pelargonium sidoides. In a randomized placebo-controlled study, an herbal compound prepared from Pelargonium sidoides called Eps 7630 was superior to placebo in relieving acute bronchitis symptoms.
  • N-acetyl cysteine (NAC). In a double-blind placebo-controlled trial, 215 people with bronchitis (84 with acute bronchitis) received 200 mg NAC three times daily for 10 days along with antibiotic therapy. NAC was found to be significantly more effective than placebo for reduction of cough, sputum volume and viscosity.
  • Eucalyptus essential oil and cineol. In a double-blind placebo-controlled study, a combination of essential oil monoterpenes containing 75 mg 1,8 cineole (combined with limonene and alpha-pinene) resulted in signs and symptoms of acute bronchitis dissipating more rapidly and completely.
  • Bromelain. Evidence has shown that bromelain may offer therapeutic benefits to individuals suffering from bronchitis and sinusitis.

2 Introduction

Acute bronchitis is responsible for about 10 million doctor’s office visits annually in the United States; it is among the top 10 reasons people seek medical help. Acute bronchitis is an inflammation of the lining of the bronchial tubes characterized by cough with or without excessive mucus production (Mayo Clinic 2011c). Although acute bronchitis can be distressing, it usually dissipates on its own in about 1 to 3 weeks (Knutson 2002; Macfarlane 2001; Tackett, McKeever 2012; Braman 2006; Wenzel 2006; A.D.A.M. 2012).

Acute bronchitis differs from chronic bronchitis, a component of the chronic obstructive pulmonary disease (COPD) spectrum (Runge 2009). In contrast to acute bronchitis, chronic bronchitis is characterized by chronic cough and sputum production occurring for at least 3 months annually during 2 consecutive years (PubMed Health 2011; Kim 2013; Mayo Clinic 2011a).

Up to 95% of cases of acute bronchitis in otherwise healthy adults are caused by viral infections, NOT bacterial infections (Hueston 1998; Tackett, Atkins 2012). A very small percentage of cases of acute bronchitis, however, are caused by bacteria (especially in people with chronic health conditions) or environmental irritants such as pollutants (Albert 2010; Tackett, Atkins 2012; Ghosh 2013; Schwartz 2004; First Consult 2013). Even though acute bronchitis is most frequently caused by viral infections, a study reported that 75% of people with acute bronchitis were prescribed an antibiotic (Tackett, McKeever 2012). This issue represents a serious public health problem, particularly considering the increasing numbers of bacterial strains that are resistant to one or multiple antimicrobial agents (Huang 2004; Erb 2007; Livermore 2000; Jones 2001). In fact, acute bronchitis has been described as the number one cause of antibiotic abuse in the United States (Runge 2009). Antibiotic therapy is not recommended for most situations in which acute bronchitis occurs (Wenzel 2006).

People who develop a cough in association with acute bronchitis often turn to over-the-counter (OTC) cough medications; however the effectiveness of these drugs is suspect. In fact, a 2012 Cochrane review found “no good evidence for or against the effectiveness of OTC medicines in acute cough” (Smith 2012). Medications that reduce inflammation, mucus buildup, and open the airways are commonly recommended to ease symptoms of acute bronchitis (Knutson 2002; Wenzel 2006; Worrall 2008; Albert 2010; Llor 2011; A.D.A.M. 2012).

Since acute bronchitis is frequently caused by viral infection, efforts should be made to prevent initial viral exposures from progressing into full-blown infection. It is important that people act quickly if they suspect they are coming down with a viral infection. Life Extension® has developed an aggressive program to support the body’s defenses during a viral attack. To read about this program in detail, refer to the Influenza and Common Cold protocols or the section at the end of this protocol. For individuals in whom the infection has already progressed to acute bronchitis, natural interventions are discussed within this protocol that may help alleviate symptoms or shorten illness duration.

3 Development of Acute Bronchitis

The bronchi are respiratory tract passages, or airways, that conduct air into the lungs (Moore 2013). Acute bronchitis is commonly thought of as a reversible inflammatory response that occurs as a result of infection or irritation of the cells that form the internal lining of the bronchi (called the epithelium) (Hueston 1998; Wenzel 2006). The inflammation and irritation associated with acute bronchitis is caused by the release of pro-inflammatory molecules by cells involved in the immune response. Viruses that infect the host in the course of acute bronchitis also affect the release of reactive oxygen species (ROS). These reactive molecules further incite the immune response and damage the epithelial cell membranes (Selemidis 2013).

4 Signs and Symptoms

The main symptom of acute bronchitis is cough that may bring up mucus, which can be clear, white, or yellow-green (Worrall 2008; A.D.A.M. 2012; Mayo Clinic 2011a). Bronchitis may also cause a sore throat, wheezing, shortness of breath, fatigue, and fever that is usually low-grade. Fever is higher and people feel sicker when they have pneumonia, a condition that sometimes may be difficult to distinguish from acute bronchitis (Gillissen 2006; A.D.A.M. 2012).

With acute bronchitis, cough persists for 5 days or more. During this period, the results of pulmonary (lung) function tests (PFTs) may be abnormal. About 40% of people with acute bronchitis have significant reductions in their forced expiratory volume (FEV; a measure of lung capacity and normal breathing) and approximately 50% experience the production of purulent (containing pus) sputum. This type of mucus, especially in previously healthy individuals, occurs from the shedding of damaged airway epithelium and cells producing inflammatory molecules (Wenzel 2006).

5 Causes and Risk Factors

Up to 95% of acute bronchitis cases are caused by viral infections (Hueston 1998; Tackett, Atkins 2012). The most common viral causes are common cold viruses (also known as rhinoviruses) and the influenza and parainfluenza viruses. The majority of remaining cases are caused by bacterial infections and environmental irritants, such as pollutants, tobacco smoke, toxic fumes, and dust (Tackett, Atkins 2012; First Consult 2013). To combat acute bronchitis caused by pollutants and other environmental triggers, one should reduce exposure to them as much as possible.  

Good hygiene, such as regular hand washing, is proven to limit the spread of viruses; therefore, it can impact the development of acute bronchitis (CDC 2012; A.D.A.M. 2012). In addition, infections with some viruses that cause acute bronchitis are more common and severe in colder weather, so taking extra precautions during winter months may help reduce risk (Dasaraju 1996; Lee 2012; Wenzel 2006). Additional risk factors include age (with very young and very old people being at higher risk for infections), immunization status (with people who did not receive vaccination being at higher risk), and working and living in crowded places, such as nursing homes, boarding schools, and military camps (First Consult 2013).

6 Diagnosis and Conventional Treatment


Diagnosis of acute bronchitis is based on clinical examination and symptoms. In some circumstances chest X-rays, sputum culture, or pulmonary function tests may help differentiate acute bronchitis from other conditions (Mayo Clinic 2011b).

Signs and symptoms of acute bronchitis sometimes resemble other respiratory diseases, and it is important that the physician correctly identify the patient’s condition in order to employ the right treatment. Acute bronchitis is distinct from health conditions like bronchiolitis (inflammation of bronchioles [ie, smaller branches of the bronchi]) or asthma (chronic inflammatory disease of the small respiratory airways), though a bout of acute bronchitis can sometimes trigger asthma and/or asthma symptoms such as wheezing (caused by bronchospasm), shortness of breath, breathlessness, and tightness in the chest (Löwhagen 2012; Killeen 2013). Another condition known as bronchiectasis can sometimes be mistaken for acute bronchitis when it is accompanied by chronic, productive cough; this condition (bronchiectasis) is marked by the destruction of the elastic and muscular tissue in the bronchial walls and their permanent dilation (Rosen 2006; Wenzel 2006). Acute bronchitis should also be differentiated from chronic bronchitis, which is a component of COPD and is characterized by coughing and sputum production on most days for at least three months of two consecutive years (Brunton 2004; Hueston 1998). On the other hand, acute bronchitis is usually self-limited and resolves within 3 weeks in about half of the cases, but around a quarter of them last longer than a month (Braman 2006; Worrall 2008).

Conventional Treatment

Antibiotics are often hastily prescribed for acute bronchitis. For example, 75% of patients with acute bronchitis were reported in one study to receive an antibiotic prescription (Tackett, Atkins 2012). However, this practice is ineffective because the vast majority of cases of acute bronchitis in otherwise healthy adults are caused by viral infection for which antibiotics are not helpful. Antibiotics treat bacterial infections, not viral infections. Accordingly, several professional medical organizations, including the American Academy of Family Physicians, U.S. Centers for Disease Control and Prevention, and Infectious Disease Society of America have issued guidelines aimed at discouraging physicians from indiscriminately prescribing antibiotics to most patients with acute bronchitis, as this can result in the development of antibiotic resistance (Gonzales 2001; American Academy of Family Physicians 2013; CDC 2012).

People with acute bronchitis are advised to refrain from intense activity, drink clear fluids (water), humidify the air, and use anti-inflammatory medication (A.D.A.M. 2012). Bronchodilators, which dilate the airways, may help reduce symptoms, but their benefits for routine use are not well established in the treatment of acute bronchitis.

There is contradictory evidence regarding the benefit of over-the-counter (OTC) cough medications. A 2012 review found “no good evidence for or against the effectiveness of OTC medicines in acute cough” (Smith 2012). However, some evidence suggests symptomatic relief with certain cough medications (Becker 2011; First Consult 2013; Smith 2012). When cough medications are used, the type of medication is generally targeted to the type of cough: expectorants for productive cough and cough suppressants (antitussives) for dry cough (Silverstone 1997; Ford 2009). Antitussives, such as codeine and dextromethorphan, may help reduce cough for individuals with acute bronchitis but are not recommended for routine use or for children (First Consult 2013). Even though cough can be a debilitating symptom in many respiratory diseases, cough suppression is particularly contraindicated when clearing secretions is an important goal (Morice 2006). The 2012 Cochrane review mentioned earlier analyzed 26 randomized, controlled trials comparing oral OTC cough preparations with placebo in children and adults suffering from acute cough. The trials showed variable results for antitussives, expectorants, and antihistamine-decongestant combinations in adults. In children, antihistamine-decongestants, antitussives, and antitussive-bronchodilator combinations were no more effective than placebo (Smith 2012).

Whether treated or not, acute bronchitis should typically resolve on its own as the inflammation within the bronchi gradually subsides and the symptoms ease. Nevertheless, the condition can be uncomfortable and frustrating, so early intervention—at the first signs of viral infection—is important to manage acute bronchitis (Matthys, Heger 2007b; WebMD 2010).

7 Novel and Emerging Strategies

Simple Blood Test Helps Avoid Antibiotic Overuse in Acute Bronchitis

Despite being aware that the vast majority of acute bronchitis cases are caused by viruses, many physicians haphazardly prescribe antibiotics for this condition. Aside from being ineffective against a viral infection, antibiotic overuse drives the emergence of potentially devastating antibiotic resistant organisms (Huang 2004; Erb 2007; Livermore 2000; Jones 2001).

Emerging evidence shows that a simple blood test can help differentiate between bacterial and viral infections, allowing physicians to refrain from prescribing antibiotics for conditions caused by viruses. This blood test assesses levels of procalcitonin (PCT), a hormone secreted by the body in response to a bacterial infection (LabCorp 2013; Chist-Crain 2004; Achanta 2012).

Several randomized, controlled trials have shown that antibiotic prescriptions in acute bronchitis have been reduced by up to 80% when procalcitonin measurements were utilized as part of the diagnostic algorithm (Schuetz 2010). A 2013 comprehensive review concluded “Procalcitonin guidance can safely reduce antibiotic usage… when used to initiate or discontinue antibiotics in adults with respiratory tract infections.” (Soni 2013; Schuetz 2010). 


The antiviral drug cimetidine (Tagamet®), which is used to help relieve heartburn, is a pharmaceutical option to provide immune system support in the context of viral infection (Palmer 1990). Cimetidine has potent immune system-boosting effects, which are thought to explain its ability to drastically reduce the severity and duration of certain viral infections (van der Spuy 1980; White 1985; Cohen 1988; Hast 1989; Wang 2008). Cimetidine, in 200 mg tablets, is available for OTC purchase (Allen 2000). It is safe for most adults and does not have serious adverse effects; while the OTC package insert indicates up to 800 mg can be taken daily, some studies have used up to 1000 mg daily without any obvious adverse effects (Harvey 1984; Rohner 1984; Choi 1993; Allen 2000).

8 Integrative Interventions

Life Extension’s Flu and Common Cold Program

Bronchitis represents a natural progression of the common cold or flu in most cases (Tackett, Atkins 2012; First Consult 2013). Therefore, taking aggressive action at the first signs of the flu or common cold is one of the best ways to prevent progression to acute bronchitis. The suggestions outlined in this section (and expanded upon in the Influenza and Common Cold protocols) represent interventions aimed at stopping a cold or the flu from progressing to acute bronchitis. At the first sign of infection, consider taking the following supplements. This program is not intended for long-term use because of the high doses. Follow these recommendations for only a few days.

  1. Zinc Lozenges: Take two zinc lozenges (13-24 mg of zinc in each lozenge) immediately and again every 2 to 3 hours for the first day or two. Then slowly reduce the dose until symptoms dissipate.
  2. Garlic: Take 9000-18,000 mg of a high-allicin garlic supplement each day until symptoms subside. Take with food to minimize stomach irritation.
  3. Vitamin D: If you do not already maintain a blood level of 25-hydroxyvitamin D over 50 ng/mL, then take 50,000 IU of vitamin D the first day and continue for 3 more days. Slowly reduce the dose to around 5000 IU of vitamin D daily. If you already take around 5000 IU of vitamin D daily, then you probably do not need to increase your intake.
  4. Cimetidine: Take 800-1200 mg daily in divided doses. Cimetidine is a heartburn drug that has potent immune enhancing properties. (It is sold in pharmacies over-the-counter.)
  5. Melatonin: 3 to 50 mg at bedtime.

Do not delay implementing the above regimen. Once a respiratory virus infects too many cells, it replicates out of control and potentially progresses, rendering strategies like zinc lozenges ineffective. Treatment must be initiated as soon as symptoms manifest!

Nutritional Strategies Studied in Bronchitis

Pelargonium sidoides. Pelargonium sidoides is a botanical highly valued in the South African region as a remedy for several respiratory tract ailments, including acute bronchitis. Several studies have examined the efficacy of the root extract of Pelargonium sidoides in the treatment of various respiratory conditions, many of which have shown promising results (Tahan 2013; Luna 2011; Bachert 2009; Lizogub 2007; Bereznoy 2003).

Specifically regarding acute bronchitis, a number of human trials have found Pelargonium sidoides to be an effective treatment option. In one randomized, double-blind, placebo-controlled trial conducted on 406 adults with acute bronchitis, an herbal compound prepared from Pelargonium sidoides called EPs 7630 was significantly superior to placebo in relieving acute bronchitis symptoms (Matthys, Lizogub, Malek 2010). In another study that expanded on the findings from this same group of subjects, the benefits of Pelargonium sidoides over placebo were found to extend to improvements in impact of patient's sickness, duration of activity limitation, patient-reported treatment outcome, and satisfaction with treatment (Matthys, Lizogub, Funk 2010).

One of the first major studies to examine the effects of Pelargonium sidoides in adults with acute bronchitis was published in 2003. Study participants received 30 drops of EPs 7630 three times daily or placebo for 7 days. In this study, the plant extract was superior to placebo in reducing the severity of bronchitis and in shortening the duration of illness, with no serious adverse reactions reported (Matthys 2003).

A study on 200 children and adolescents aged 1 to 18 with acute bronchitis showed that Pelargonium sidoides administered in liquid extract form over a 7-day period (30 drops/day for children 1-6 years; 60 drops/day for children 6-12 years; and 90 drops/day for children 12-18 years) was significantly superior to placebo in relieving acute bronchitis symptoms (Kamin 2010). In a separate randomized, double-blind, placebo-controlled study, 217 adults with acute bronchitis received 30 drops of EPs 7360 three times daily, 30 minutes before or after a meal, or placebo for 7 consecutive days. This liquid extract of Pelargonium sidoides was superior to placebo in improving scores on a standardized bronchitis symptom assessment (ie, relieving specific symptoms such as cough, chest pain upon coughing, sputum, and shortness of breath). Moreover, very good subject satisfaction was seen during the study (Matthys, Heger 2007a).

German researchers studied the effects of Pelargonium sidoides in 2099 people with acute bronchitis. In this study, EPs 7630 was administered 3 times daily, 30 minutes before a meal, for a 14-day period. The EPs 7630 solution contained 80 g EPs 7630 in a 100 mL solution, and participants received 10 drops if under 6 years of age, 20 drops if between 6 and 12 years, and 30 drops if over 12 years. The study found that average symptom scores decreased significantly across the study group. Moreover, only 26 subjects reported an adverse reaction to the treatment regimen, none of which were serious (Matthys, Kamin 2007). A different study published by a group of scientists in Russia examined the effects of Pelargonium sidoides versus placebo in a double-blind, randomized fashion in 124 adults with acute bronchitis. Study participants received 30 drops of EPs 7630 three times daily or placebo. Results of a standardized assessment after 7 days of treatment showed Pelargonium sidoides to be superior to placebo for relief of acute bronchitis symptoms, with nearly 70% of subjects responding to treatment within the first 4 days (Chuchalin 2005).

A 2008 meta-analysis concluded, “There is encouraging evidence from currently available data that P. sidoides is effective compared to placebo for patients with acute bronchitis” (Agbabiaka 2008).

Laboratory studies indicate that EPs 7630 may act through multiple mechanisms to help fight respiratory tract conditions (Kolodziej 2003; Thale 2011). First, it possesses anti-infective properties by increasing phagocytosis (ie, a mechanism used by white blood cells to remove pathogens and cellular debris) (Conrad 2008). Second, infected cells treated with EPs 7630 showed augmented activation of defense mechanisms (Kolodziej 2007). Finally, EPs 7630 has been found to stimulate ciliary beat frequency which may help clear excess mucus (Neugebauer 2005).

Thyme. Thyme extract is a promising therapeutic option for the cough that occurs in acute bronchitis. A double-blind, placebo-controlled study used extracts of a combination of thyme leaf and primrose root to assess their ability to reduce cough on an objective scale, the Bronchitis Severity Score. On days 7 to 9, an average decrease of over 67% in coughing fits was seen in the thyme-primrose group. A 50% reduction in cough was achieved by the extract-combination treatment approximately 2 days earlier compared to placebo (Kemmerich 2007).

In another double-blind study, 361 people with acute bronchitis received a thyme-ivy combination for 11 days; researchers reported that its administration was superior to placebo for reduction of coughing fits (Kemmerich 2006). Another study examined an herbal combination that includes thyme extract called Bronchipret®. The authors reported Bronchipret® (containing 160 mg of thyme extract) was as effective as synthetic medications for the clinical outcomes of bronchitis in children and adults. In the adult subgroup analysis, there was a tendency for better results and less adverse reactions with the herbal combination as compared to synthetic medications (Ernst 1997).

N-acetyl cysteine. N-acetyl cysteine (NAC), a slightly modified version of the natural amino acid cysteine, has both mucolytic (can break down or “thin” mucus) and antiviral properties (Brochard 1980; Mata 2011). NAC has been shown to inhibit replication and ameliorate the inflammatory reaction caused by the influenza virus and other respiratory viruses (Hui 2013; Mata 2011). In experimental studies, NAC significantly offset the oxidative and inflammatory stress through multiple mechanisms, and it decreased the severity of influenza symptoms in animals and humans (McCarty 2010; Geiler 2010). NAC is also thought to inhibit intracellular signaling pathways that promote viral propagation (McCarty 2010). In addition, NAC is a precursor of glutathione, a potent antioxidant (Johnson 2012). A small-scale, placebo-controlled trial of treatment for serious inflammatory symptoms inflicted by mustard gas inhalation showed that 1200 mg oral NAC daily for 4 months significantly improved respiratory function in the control group (Ghanei 2008). Another trial showed that 1800 mg NAC daily for 4 months improved cough, shortness of breath, and sputum production (Shohrati 2008).

In a double-blind, placebo-controlled trial, the mucolytic activity of NAC was evaluated in 215 people with bronchitis (84 of which had acute bronchitis). Subjects were given 200 mg NAC three times daily for 10 days along with antibiotic therapy. NAC was found to be significantly more effective than placebo for reduction of cough, sputum volume and viscosity (Brochard 1980).

Eucalyptus essential oil and cineol. Inhaled eucalyptus essential oils have been used in traditional medicine to treat respiratory diseases including bronchitis. These essential oils have antibacterial, antiviral, and antifungal activity against pathogens implicated in these conditions (Elaissi 2012; Astani 2010; Yang 2010).

Essential oils contain many constituents including compounds called monoterpenes, which are thought to be at least partly responsible for their antiviral properties (Astani 2010). The eucalyptus monoterpene 1,8 cineole has been found to significantly decrease the signaling ability of NF-kappaB (NF-κB), a "master" pro-inflammatory molecule. NF-κB activates the production of many inflammatory molecules in response to infection (Greiner 2013). Inhibitors of NF-κB, which is part of a signaling pathway that the influenza virus may "hijack" after infecting human and animal cells, were shown to protect animals against highly pathogenic influenza viruses, and this molecule may become the target of novel anti-influenza drugs (Haasbach 2013).

One combination of essential oil monoterpenes that includes 75 mg of 1,8 cineole (in combination with limonene and alpha-pinene) has been found to be effective for acute bronchitis. In a double-blind, placebo-controlled clinical trial, 676 people with acute bronchitis were given either 300 mg of the combination four times daily, antibiotics, or placebo. The researchers reported signs and symptoms dissipated more rapidly and more completely for those taking the essential oil combination than those in the placebo group. The authors concluded that the combination of essential oil constituents “is a well-evidenced alternative to antibiotics for acute bronchitis without specified infective agent, without the risk to promote the development of bacterial resistance” (Matthys 2000). A 2013 multi-center, randomized, controlled trial found that coughing fits decreased by 62% after one week of treatment with the combination. In addition, there was less daytime coughing fits, difficulty coughing up, and sleep disturbance due to nighttime coughing as compared to placebo (Gillissen 2013).

Investigational Natural Interventions

Vitamin E. There is evidence that supplementation with vitamin E may improve or exert a protective effect upon lung health. Supplementation with gamma-tocopherol, an important form of vitamin E, decreased overall oxidative stress and suppressed the excessive release of inflammatory chemicals from the white blood cells of healthy and asthmatic human subjects (Wiser 2008). Gamma-tocopherol also showed anti-inflammatory effects in the upper airways of an animal model of allergic rhinosinusitis (Wagner 2009). A mouse model of airway inflammation caused by nitrogen mustard gas revealed that vitamin E decreases acute lung inflammation and inhibits collagen formation in the lungs (Wigenstam 2009). In addition, a study reported there is a benefit when incorporating vitamin E into pandemic influenza vaccines as an adjuvant (ie, a substance added to vaccines to enhance their immune response). One such adjuvant containing vitamin E (as alpha[α]-tocopherol) is known as AS03. In a trial of 1340 healthy individuals inoculated against the pandemic H1N1 influenza virus, those who received the vaccine with AS03 achieved the strongest immune response against the virus (Ferguson 2012).

Curcumin. Curcumin, which is derived from the spice turmeric, is a natural anti-inflammatory agent. Curcumin has an established role in protecting lung tissue against the inflammation induced by chemical and infectious agents (Punithavathi 2000; Aggarwal 2009; Parveen 2013). Curcumin was shown to reduce inflammatory response in the lung epithelium of mice (Yen 2013). In a study of 2478 Asian adults over the age of 55, dietary intake of curry (containing curcumin) at least once monthly was significantly linked to better lung function, even in current and past smokers (Ng 2012).

Bromelain. Bromelain, an extract of the pineapple plant, has anti-inflammatory, immunomodulatory, and mucolytic properties (Bernkop-Schnürch 2000; Hale 2005; Secor 2005; Grabovac 2006). Bromelain is a collective term for enzymes found in pineapple fruit, stem, and leaves (Hale 2005; Pavan 2012; Vilanova Neta 2012). These enzymes are proteolytic, meaning they break down proteins into their constituent peptides and amino acids. Bromelain may offer therapeutic benefits to individuals suffering from bronchitis and sinusitis (Pavan 2012). 


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