Irritable bowel syndrome is characterised by cramping, abdominal pain, bloating, constipation and diarrhoea. This team proposed that St. John’s wort may help improve IBS symptoms because antidepressant drugs are often used to treat the condition and have some level of success.
In the United Kingdom, 16% of patients with IBS had seen an alternative medicine provider in 1986, and 20 years later, in 2005, 51% of patients with IBS were using complementary or alternative medicine.
Up to 60 percent of people with IBS also have psychological symptoms such as anxiety and depression for which the relationship between CNS and ENS communication has been suggested as a therapeutic inroad. Some research suggests that the neurotransmitter serotonin may be linked to normal gastrointestinal functioning, as nearly 95 percent of serotonin in the body is located in the digestive tract.
People with IBS have been shown to have fewer serotonin receptors, causing abnormal levels of serotonin in the gastrointestinal tract and possibly leading to IBS symptoms. However, the potential relationship between IBS and depression is still unclear.
In the study, 70 adults with IBS were randomly assigned to take St. John’s wort or placebo daily for 12 weeks. The participants reported their overall bowel symptoms, as well as the frequency and severity of diarrhoea, constipation, abdominal pain or discomfort and bloating. The authors concluded that St. John’s wort was less effective than placebo.
What Else Can We Use?
Other therapies have been studied as potential treatment options for IBS. For instance, good evidence suggests that hypnotherapy may lower the sensory and motor component of the gastrocolonic response in patients. Peppermint and probiotics may also improve symptoms of IBS, such as abdominal pain, bloating and stool frequency. There is also some evidence that probiotics may reduce swelling and improve quality of life. However, not all studies reported beneficial effects and the correct selection of effective probiotics, rather than un-trialled combinations may well increase successful outcomes.
 Saito YA, Rey E, Almazar-Elder AE, Harmsen WS, Zinsmeister AR, Locke GR, Talley NJ. A randomized, double-blind, placebo-controlled trial of St John’s wort for treating irritable bowel syndrome. Am J Gastroenterol. 2010 Jan;105(1):170-7. Epub 2009 Oct 6. View Abstract
 Kong SC, Hurlstone DP, Pocock CY et al. The incidence of self-prescribed oral complementary and alternative medicine use by patients with gastrointestinal diseases. J Clin Gastroenterol 2005;39:138–141. View Abstract