I felt I had to share this (before looking into the claim) because it was so provocative. Enteric- coated peppermint oil is the answer.

Okay, I can’t help myself. I just did a little search and came up with a couple of reports that look credible and useful.

From Univ of Maryland (Integrative) Medical Center:

Irritable Bowel Syndrome (IBS)

Several studies have shown that enteric coated peppermint capsules can help treat symptoms of IBS, such as pain, bloating, gas, and diarrhea. (Enteric coated capsules keep peppermint oil from being released in the stomach, which can cause heartburn and indigestion.) However, a few studies have shown no effect. One study examined 57 people with IBS who received either enteric coated peppermint capsules or placebo twice a day for 4 weeks. Of the people who took peppermint, 75% had a significant reduction of IBS symptoms. Another study comparing enteric coated peppermint oil capsules to placebo in children with IBS found that after 2 weeks, 75% of those treated had reduced symptoms. Finally, a more recent study conducted in Taiwan found that patients who took an enteric coated peppermint oil formulation 3 - 4 times daily for one month had less abdominal distention, stool frequency, and flatulence than those who took a placebo. Nearly 80% of the patients who took peppermint also had alleviation of abdominal pain.

Source: Peppermint | University of Maryland Medical Center http://umm.edu/health/medical/altmed/herb/peppermint#ixzz2yFgoT0my 
University of Maryland Medical Center 

And here, how embarrassing, is a 1997 paper from the Journal of Gastroenterology, what also found it useful.

Forty-one patients on Colpermin (79%) experienced an alleviation of the severity of abdominal pain (29 were pain-free); 43 (83%) had less abdominal distension, 43 (83%) had reduced stool frequency, 38 (73%) had fewer borborygmi, and 41 (79%) less flatulence. Corresponding figures for the placebo group were: 21 patients (43%) with reduced pain (4 were pain-free), 14 (29%) with reduced distension, 16 (32%) with reduced stool frequency, 15 (31%) with fewer borborygmi, and 11 (22%) with less flatulence. Symptom improvements after Colpermin were significantly better than after placebo (P < 0.05; Mann-Whitney U-test). One patient on Colpermin experienced heartburn (because of chewing the capsules) and one developed a mild transient skin rash. There were no significant changes in liver function test results. Thus, in this trial, Colpermin was effective and well tolerated.

http://link.springer.com/article/10.1007/BF02936952; http://www.ncbi.nlm.nih.gov/pubmed/9430014

Seems CVS, Walgreens, Amazon and others have known this long before I found out as well. 

Finally, here is a .pdf of enteric-coated peppermint oil for treatment of small intestine bacterial overgrowth (there’s, surprise, an acronym for it too!: SIBO). I guess I still have alot to learn.

http://www.altmedrev.com/publications/7/5/410.pdf

Mike Barr is a board certified acupuncturist and herbalist and can be reached at Manhattan Acupuncture Associates, with offices at Columbus Circle and Flatiron. His expertise and interests include sports acupuncture, pain syndromes, liver health, immunological support, low energy, mood disorders, anxiety, insomnia, GI complaints, and herbal and acupuncture approaches to getting off/putting off prescription medications of unsatisfactory or unclear benefit, and in helping to manage the side-effects of other necessary and life-saving biomedical interventions. He has also been busy exploring the application of East Asian herbal therapies, and specific acupuncture protocols, for all aspects of sexual health and anti-senescence.