It's a painful disorder that can really stop life right in its tracks.
About 20 percent f adults suffer with Irritable Bowel Syndrome and now researchers believe they have a way to control it.
Sandra Hughes reports from Los Angeles.
Amy McMahon works out and eats right and it shows, so when this 50 year old began to bloat uncontrollably she knew something was wrong.
She told Sandra, "My stomach was distended, I'm going to say 7 months pregnant it was just this area and my skin turned really red."
It took nine months of failed treatments and testing before McMahon was diagnosed with Irritable Bowel Syndrome.
Amy said, "It was awful, it was really awful by midday I'd have to lay down."
Doctor Mark Pimentel treated her at Cedars Sinai Medical Center with an antibiotic called Rifaximin.
Of 12-hundred IBS patients taking part in the study, 40 percent said they felt better with the antibiotic and symptoms went away.
The drug targets bacteria in the small intestine.
Dr. Pimentel says, "It's not bad bacteria, it's that they don't belong in the small intestine."
Pimentel and his researchers were the first to figure out that bacteria was causing IBS, until then, doctors would often link IBS to stress and treat sufferers with anti-depressants.
The diahrrea and constipation of IBS could be reduced with medications but nothing would last.
Dr. Pimental told us, "This is the first antibiotic, this rifaxamin that treats IBS, they get better and stay better. Every other therapy we've used as soon as you stop it they get sick again."
Currently Rifaximin is not FDA approved to treat IBS.
Although doctors can still choose to prescribe it.
Amy is thankful she took part in the clinical trial. "I'm feeling really good."
Three years later she's still symptom free.
Right now Rifaximin is only FDA approved to treat traveler's diarrhea and a brain condition caused by liver problems.