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 One drug that had shown promise, Zelnorm, was withdrawn from the market for safety issues. Another, Lotronex, was temporarily withdrawn, and then re-approved, but only under strict limitations.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 oil is widely used for IBS, and the evidence suggests that it is probably useful. A majority of placebo-controlled studies have found peppermint oil to be more effective than placebo.7-12,34,49,64,67 However, most of these studies are small.

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

Numerous double-blind trials indicate that various probiotics ("friendly" bacteria) may be helpful for IBS.15,16,25,27,28,35,47,50,51,54-56,61,69,70

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 Another study examined the effects of 4 weeks of 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 In a review of 3 randomized trials, Lactobacillus rhamnosus GG was associated with improvement in symptoms, especially a reduction in abdominal pain, among 393 children with IBS.72

In another randomized trial, 266 women with constipation who consumed yogurt containing B. 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.60

And finally, a 4-week randomized trial involving 122 people with IBS found evidence that B. bifidum improved symptoms and quality of life compared to placebo.78

Benefits have also been seen in other smaller, double-blind trials, as well, using Lactobacillus plantarum,25, 27L. acidophilus,16,55L. rhamnosus,47L. salivarus,51,63 and B. infantis,51 as well as proprietary probiotic combinations including various strains.28,35,54,62 One such combination, called VSL#3, contains B. longum, B. infantis, L. acidophilus, L. plantarum, L. casei, L. bulgaricus, and Streptococcus thermophilus. In a double-blind, crossover trial, 59 children aged 5-18 years old were randomized to receive VSL#3 or placebo for 6 weeks.69 After a 2-week "wash-out" period, the children were switched to the other treatment. VSL#3 was associated with a reduction in symptoms, including abdominal pain, bloating, and gas.

Of course, not all studies have supported the use of probiotics as a treatment for IBS.26,36,57 One randomized trial involving 90 people with diarrhea-predominant IBS found Saccharomyces boulardii to be more effective than placebo at improving quality of life.70 But, the probiotic did not seem to improve the actual symptoms of IBS. 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

Lactobacillus plantarum 299v failed to provide significant improvements in abdominal pain, bloating, or quality of life when compared to placebo in a randomized trial with 81 adults over an 8 week period.83

Probiotics Lactobacillus, Bifidobacterium, Escherichia, and Streptococcus (alone or in combination) were evaluated in a review of 37 randomized trials. Priobiotics were associated with fewer global symptoms, abdominal pain, bloating, and flatulence when compared to placebo. There were no differences found in urgency-related symptoms. Although probiotic therapy appears effective, the right combination of strains remains unknown.82

For more information, see the full Probiotics article.

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 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

In a review of 19 randomized trials with 1,510 people, Chinese herbal medicine was associated with a greater cure rate, and reduced recurrence of constipation-dominant IBS compared to traditional Western treatments. The Chinese herbal medicines focused on the liver and were given over a period of 3-12 weeks. However, there were many biases in the trials, which makes outcomes less reliable.80

Chinese herbal medicine significiantly improved symptoms in people with constipation-related IBS in one randomized trial. Extracts from seven herbs (or placebo) were given to 125 adults in a randomized trial and taken for 8 weeks. However, the improvement in IBS symptoms faded during the 16 weeks follow up period after treatment was stopped. There were no differences between those who took the herbal medication or the placebo in the follow up.85

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

One randomized trial with 120 patients found that anise oil significantly improved IBS symptoms, including abdominal pain, bloating, diarrhea, constipation, fatigue, and quality of life compared to peppermint oil and placebo. Anise oil capsules (200 mg) were taken 3 times a day for 4 weeks.86

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.31,75,76,77 In one trial, 90 people with IBS were randomized to receive hypnotherapy provided by an experienced psychologist or supportive therapy.75 In a second related trial, 48 patients were randomized to hypnotherapy with a less experienced psychologist or to a waiting list. In both trials, which lasted three months, those who received hypnotherapy showed an improvement in their IBS symptoms. In another trial, the addition of hypnotherapy to supportive talks and usual care improved IBS symptoms when compared to supportive talks and usual care alone in a randomized trial of 100 adults suffering from severe IBS. Over 54% of patients receiving hypnotherapy had symptom improvement for up to 15 months compared to 25% in the control group.79 In a review of 5 trials with 278 patients, hypnotherapy was associated higher levels of symptom improvement when compared to a control group or usual care. There were some biases in the studies, but hypnotherapy has been shown to be a beneficial for people with IBS.81

Hypnotherapy has also been studied for IBS in children.76 Fifty-two children with IBS or functional (unknown cause) abdominal pain were randomized to hypnotherapy or standard care . After 3 months of treatment, those in the hypnotherapy group reported less pain. A follow-up study found that these effects lasted for almost 5 years in about 2/3 of the children.77

Relaxation therapy may also be helpful.53,54,66 ,68 For example, in a randomized study involving 75 women with IBS, those who participated in mindfulness meditation therapy experienced more of an improvement in their symptoms compared to those who participated in a support group.71 A review of 6 trials with 255 patients found relaxation therapy had higher incidence of some improvement. In these trials, relaxation therapy was compared to a control group or usual care. Although the results were not conclusive, the review found relaxation therapy to be beneficial.81

Acupuncture has been proposed as a treatment for IBS. However, a number of studies, including 2 systematic reviews, have not found strong evidence to support the use of acupuncture for this condition.32,33,43,65,73,74 The most recent review included 17 trials involving 1,806 people that compared real acupuncture to a range of control groups, such as sham acupuncture, psychotherapy and medication, among others.74 In the 5 trials that included real versus sham acupuncture, there were no significant differences between the two treatment groups on IBS symptoms. Other trials without a placebo control showed more of a positive effect, though. For example, people receiving acupuncture treatments reported more symptom relief compared to those receiving psychotherapy or medication .

A review of 11 low-quality randomized trials compared moxibustion or moxibustion with acupuncture to drug therapy. Moxibustion (the use of heat to stimulate acupuncture points) was associated with improved IBS symptoms when compared to drug therapy alone. However, the quality of the sutdies may have influenced the outcomes. Researchers in all acupuncture trials listed above highlighted the need for more studies.84

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