Orlistat and Alli are labels for Xenical

Orlistat (Alli)  is used to help obese people who fit certain weight and height requirements lose weight and maintain weight loss.

Orlistat works in your intestines, where it blocks some of the fat you eat from being absorbed. This undigested fat is then eliminated in your bowel movements.

Use Orlistat together with a reduced-calorie diet. The weight management effects of Orlistat continue only as long as you are taking it.

Orlistat acts by blocking the absorption of about one-quarter the fat a patient consumes. That fat is then passed out of the body in stools, which can be loose or oily as a result. New: Xerisan

Glaxo said the drug helps the overweight slim down only when combined with a diet and exercise regimen. Orlistat's actual effect on weight loss is "gradual and modest," said Steve Burton, Glaxo's vice president of weight control.

"There is no magic pill for weight loss and Orlistat is not a magic pill. Orlistat is a tool that will help people control their calorie intake and modify their diet," said John Dent, the pharmaceutical company's senior vice president of research and development.

On January 23, 2006, a US Food and Drug Administration advisory panel voted 11 to 3 to recommend the approval of an OTC formulation of Orlistat (planned to be marketed under the name Alli by GlaxoSmithKline). The proposed product will consist of 60 mg dosage units, similar to the OTC products available elsewhere.

Orlistat / Alli Side effects

The unpleasantness of the drug's side effects, including "involuntary leakage" of undigested fat, should limit its abuse, said Dr. Howard Eisenson, director of the Duke Diet and Fitness Center in Durham, N.C.

"I think to some extent, the side effects will limit the potential for abuse, because the side effects are uncomfortable or messy," said Eisenson, adding he has no financial ties to the drug or its manufacturer.