Herbal Therapy Is Equivalent to Rifaximin for the Treatment of Small Intestinal Bacterial Overgrowth

Patients with small intestine bacterial overgrowth (SIBO) have chronic intestinal and extra-intestinal symptoms that adversely affect their quality of life. SIBO is becoming an increasingly significant problem in clinical practice as its manifestations can be variable, ranging from a full-blown enteropathy that causes profound malabsorption and malnutrition resembling celiac disease, to mild symptoms that overlap with IBS. 

Although the overall prevalence of SIBO in the general public is unknown, a meta-analysis has shown that the prevalence of SIBO is approximately 56% among patients with irritable bowel syndrome (IBS). 

Given the role of the gut microbiome in health and dysbiosis in disease, SIBO is an important entity in clinical practice to recognize and treat.1

The gut microbiota is a finely balanced ecosystem that helps regulate key vital functions for the host, including immunity, barrier defense, biotransformation of toxins and carcinogens, and much more. Imbalances in the gut microbiome (also known as dysbiosis) have been linked to the development of disorders of mood and behavior, Alzheimer’s disease, and numerous gastrointestinal and systemic disorders including inflammatory bowel disease, diabetes, obesity, and cardiovascular disease. 

Bacterial dysbiosis in SIBO can disrupt the integrity of the intestinal walls, allowing bacterial endotoxins to escape into the bloodstream, and the release of pro-inflammatory cytokines, creating inflammation. SIBO can have a number of extra-intestinal manifestations such as rosacea, restless legs syndrome, arthralgias, anemia, interstitial cystitis, chronic prostatitis, and polyneuropathy.1 A large body of work has linked bacterial dysbiosis to non-alcoholic steatohepatitis and progression of alcoholic liver disease, non-alcoholic fatty liver disease, obesity, and others.

The current mainstream treatment of SIBO is limited to oral antibiotics which yield only variable success, and are often accompanied by adverse changes to the gut microbiome, along with a wide range of side effects and toxicity (Clostridium difficile colitis, antibiotic induced diarrhea, anaphylaxis, Steven’s Johnson reactions, hemolytic-uremic syndrome, just to name a few). Recurrence rates after treatment with antibiotics is high as evidenced by high positivity with breath retesting. The fear of bacterial resistance including opportunistic infections such as Clostridium difficile raises concerns among recurrent antibiotic users. Further, the antibiotics used for SIBO come at a high price tag for patients.1 Herbal remedies and nutraceutical supplements are recognized as an important treatment for IBS patients, and a number of herbs have a long tradition of antimicrobial activity. Thus, researchers hypothesized that the use of plant extracts possessing antimicrobial activity would be as effective as antibiotic therapy for patients with the diagnosis of SIBO, without the adverse effects. So how do herbal therapies stack up against antibiotics??

A notable study by Chedid, Victor et al. tested the remission rate of SIBO using either the antibiotic rifaximin - the antibiotic that has been most widely recognized and published for its use in the treatment of SIBO, or herbal treatments. The patients who participated were offered either rifaximin 1200 mg daily vs herbal therapy for 4 weeks, with repeated breath testing post-treatment. The results showed that herbal therapies are at least as effective as rifaximin for resolution of SIBO! Herbals also appear to be as effective as triple antibiotic therapy for SIBO rescue therapy for rifaximin non-responders!!1

The cost of the herbal regimen is traditionally not covered by commercial insurance; however, the cost of the herbals is relatively low and many individuals did find coverage through their flexible spending accounts. 

In conclusion, patients can have a choice between antibiotic or herbal therapy depending on their individual preference with similar response rates and safety profiles. In addition, patients who are refractory to rifaximin can receive herbal therapy as a potential rescue therapy with equivalent results to triple antibiotics. This decision is left at the discretion of the treating physician and the patient depending on the clinical setting and the patient’s inclination. 

Herbs examined in the study included:

Oregano (Origanum vulgare): directly kills or strongly inhibits the growth of intestinal microbes. Oil of oregano has other beneficial properties such as inducing apoptosis in human colon cancer caco2 cells. 

Wormwood (Artemisia absinthium): substantial antimicrobial and anti-inflammatory properties that may be important to the pathogenesis of SIBO and has been used to successfully induce remission of Crohn’s Disease.

Lemon balm (Melissa officinalis): also offers anti-anxiety and antidepressant effects that may benefit patients with IBS.

Coptis root (Coptis chinensis): growth-inhibitory effects on human bacteria.

Thyme (Thymus vulgaris): potent antimicrobial and anti-inflammatory actions, inhibits the growth of Escherichia coli O157: H7 and Staphylococcus aureus. 

Indian Barbarry root (Berberis aristata): contains berberine and has antimicrobial, anti-inflammatory, and antidiarrheal properties.

Horsetail AKA Shavegrass (Equisetum arvense): broad spectrum of a very strong antimicrobial activity against a variety of enteric microorganisms including Staphylococcus aureus (S aureus), Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enteritidis and the fungi Aspergillus niger and Candida albicans. 

Olive leaf (Olea europaea): inhibits the growth of a number of staphylococcal species including S aureus. 

1. Chedid V, Dhalla S, Clarke JO, et al. Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Glob Adv Health Med. 2014;3(3):16-24. doi:10.7453/gahmj.2014.019