ORLANDO, Fla. -- A new antibiotic has proven to be extremely effective for treating people with irritable bowel syndrome (IBS), Channel 4's medical news provider, Ivanhoe, is reporting.

IBS is one of the top 10 most common chronic medical conditions in the United States. It causes abdominal pain, cramping, bloating, diarrhea and constipation.

The problems usually begin in early adult life. Most medications for IBS work by relieving the symptoms, but not actually treating the cause of the disorder.

Researchers at Cedars-Sinai Medical Center, Los Angeles conducted a study to determine if a non-absorbed antibiotic, rifaximin, is more effective than a placebo for reducing the symptoms of IBS.

For this study, 87 patients were questioned before and after treatment with rifaximin and asked to keep a symptom diary for 10 weeks afterwards.

"This study is very different. Nnormally you take a drug [for IBS] and the drug does something to the movement of the gut that is beneficial," said Mark Pimental, M.D, director of the GI Motility Program at Cedars-Sinai and the study's principal investigator. "You take the drugs and they work, but as soon as you stop taking them, they stop working. With other drugs you are just treating the cause of IBS, you're just compensating for what IBS does symptomatically."

Pimental and colleagues were working under the theory that IBS is caused by bacterial overgrowth in the gut. With the antibiotic rifaximin, 99.6 percent of the drug is not absorbed, meaning the drug does not get into the bloodstream, so patients are much less likely to have any side effects at all but the bacteria in the gut is controlled.

Refaximin is currently FDA approved for traveler's diarrhea but not for all the symptoms associated with IBS. Another antibiotic, neomycin, was effective but not as much as the rifaximin.

"With neomycin maybe three out of 10 patients would get better. With rifaximin, seven out of 10 got better. Until now there was no antibiotic [for IBS] in the U.S. that could get that rate of response," Pimental said.

Everyone who has IBS may be a candidate, with the exception of patients who have had bowel surgery. The antibiotic itself doesn't last long, but the effects do. Patients felt relief from symptoms during the 10 weeks of follow-up.

The researchers seem convinced that this drug does the trick with no reported side effects.

"It makes patients better and they stay better," Pimental said.

This article was reported by Ivanhoe.com, who offers Medical Alerts by e-mail every day of the week. To subscribe, go to Ivanhoe.com/newsalert.