The term IBS is used to describe chronic colon problems that occur in the absence of an identifiable medical cause. Common symptoms include alternating diarrhea and constipation, excess intestinal gas, intestinal cramping, uncomfortable bowel movements, abdominal discomfort following meals, and excessive awareness of the presence of stool in the colon. Despite all these distressing symptoms, in IBS, the intestines appear to be perfectly healthy when they are examined. Thus the condition belongs to a category of diseases that physicians call “functional.” This means that while the function of the bowel seems to have gone awry, no injury or disturbance of its structure can be discovered. (The analogous problem in the stomach is called dyspepsia , and the two conditions frequently overlap.)

Because the cause of IBS is not understood, conventional medical treatment of IBS is highly inadequate. One drug that had shown promise, Zelnorm, was withdrawn from the market for safety issues. Another, Lotronex, was temporarily withdrawn, and then re-approved, but only under strict limitations. Other medical treatment approaches for IBS include increased dietary fiber, drugs that reduce bowel spasm, and drugs to address constipation or diarrhea as needed. In addition, various forms of psychotherapy, including hypnosis, have been tried, with some success. 1-6

Principal Proposed Natural Treatments

Peppermint

Peppermint oil is widely used for IBS, and the evidence suggests that it is probably useful. At least 9 out of 13 placebo-controlled studies found peppermint oil more effective than placebo. 7-12,34,49,64 However, most of these studies were small.

For more information, including dosage and safety issues, see the full Peppermint article.

Probiotics

Numerous double-blind trials indicate that various probiotics ("friendly" bacteria) may be helpful for IBS. 15,16,25,27,28,35,47,50,51,54-56,61

For example, in a 6-week, double-blind, placebo-controlled trial of 274 people with constipation-predominant IBS, in which constipation is a more significant symptom than diarrhea, use of a probiotic formula containing Bifidobacterium animalis significantly reduced discomfort and increased stool frequency. 50 In another randomized trial, 266 women with constipation who consumed yogurt containing Bifidobacterium animalis and the prebiotic fructo-oligosaccharide twice daily for two weeks experienced significant improvement in their symptoms compared to women consuming regular yogurt as a placebo. 60Prebiotics are substances that encourage the growth of beneficial bacteria in the colon.

Another study examined the effects of 4 weeks treatment with L. plantarum on intestinal gas in 60 people with IBS. This study found benefits that persisted for an entire year after treatment stopped. 15

Benefits were seen in 8 other small, double-blind trials as well, using L. plantarum , 25, 27L. acidophilus , 16,55Lactobacillus rhamnosus , 47L. salivarus , 51,63 and Bifidobacterium , 51 as well as proprietary probiotic combinations including various strains. 28,35,54,62

However, there have been a number of negative studies as well. 26,36,57

Two studies that pooled previous randomized trials on the use of probiotics for IBS came to similar conclusions: probiotics appear to offer some benefit, most notably for global symptoms and abdominal discomfort. However, these two studies were unable to determine which probiotic species were most effective. 58,59

For more information, see the full Probiotics article.

Flaxseeds

In a double-blind study, 55 people with chronic constipation caused by IBS received either ground flaxseed or psyllium seed (a well-known treatment for constipation) daily for 3 months. 17 Those taking flaxseed had significantly fewer problems with constipation, abdominal pain, and bloating than those taking psyllium. The flaxseed group had even further improvements in constipation and bloating while continuing their treatment in the 3 months after the double-blind study ended. The researcher concluded that flaxseed relieved constipation more effectively than psyllium.

For more information, see the Flaxseed article.

Chinese Herbal Medicine

Chinese herbal medicine is traditionally practiced in a highly individualized way, with herbal formulas tailored to the exact details of each person’s case. In a double-blind, placebo-controlled trial, 116 people with IBS were randomly assigned to receive individualized Chinese herbal treatment, a “one-size-fits-all” Chinese herbal formulation, or placebo. 29 Treatment consisted of 5 capsules 3 times daily, taken for 16 weeks. The results showed that both forms of active treatment were superior to placebo, significantly reducing IBS symptoms. However, the individualized treatment was no more effective than the “generic” treatment. Similar results were seen in another study as well. 44

For more information on this complex medical system, including important safety issues, see the Traditional Chinese Herbal Medicine article.

Other Proposed Natural Treatments

One study found evidence that pancreatic digestive enzymes (including proteolytic enzymes plus other enzymes called lipases) might be helpful for reducing the flare-up of IBS symptoms that may follow a fatty meal. 30

Three small studies suggest that use of the supplement melatonin might reduce symptoms of IBS; 38-39,46 it has been suggested that the hormone melatonin may have an effect on the nervous system in the digestive tract.

An herbal combination containing candytuft , matricaria flower , peppermint leaves , caraway , licorice root , and lemon balm has shown some promise for IBS. 37

In one double-blind trial, a combination of lemon balm , spearmint, and coriander showed some promise for reducing symptoms of diarrhea-dominant IBS. 45

The herbs Coleus forskohlii and slippery elm as well as the supplement glutamine are also sometimes recommended for IBS, but there is no meaningful evidence as yet that are helpful.

One double-blind study failed to find either the herb fumitory or an herbal relative of turmeric helpful for IBS. 40

The prebiotic supplement fructo-oligosaccharides has been advocated as a treatment for IBS. However, research results are currently inconsistent at best. For example, a s6-week, double-blind study of 105 people with mild irritable bowel syndrome compared 5 g of fructo-oligosaccharides daily against placebo, and returned conflicting results. 52 According to some measures of symptom severity employed by the researchers, use of FOS led to an improvement in symptoms; however, according to other measures, FOS actually worsened symptoms. 19 Conflicting results, though of a different kind, were also seen in a 12-week, double-blind, placebo-controlled study of 98 people. 41 Treatment with FOS at a dose of 20 g daily initially worsened symptoms, but over time this negative effect wore off. At no time in the study were clear benefits seen, however. On a positive note, one study did find benefit with a combination prebiotic-probiotic formula. 42

Food allergies may play a role in IBS, and diets based on identifying and eliminating allergenic foods might offer some benefit. 18-24,48

Hypnotherapy has shown some promise for IBS, 31 as has relaxation therapy . 53,54

Acupuncture has been proposed as a treatment for IBS. However, study results have thus far failed to show it effective. For example, a 13-week study of 60 people with IBS found fake acupuncture just as beneficial as traditional acupuncture. 32 Two other studies also failed to find benefit. 33,43

For a discussion of homeopathic approaches to irritable bowel syndrome, see the Homeopathy database.