Mechanism of action
Xenical inhibits lipases, which are enzymes in the body that break down fats found in the food you eat so that they can be absorbed in the intestines. Therefore, when you take Xenical and eat a food that has fat, it reduces the amount of fat that is absorbed into the body by roughly 30 percent. This can help with managing weight and weight loss7.
Xenical can cause several common side effects. In terms of GI effects, it can cause gas, (sometimes with discharge), urgent or increased bowel movements, oily or fatty stools, loose stools, discolored stool, nausea, vomiting, diarrhea, and rectal and stomach pain. Xenical can also cause weakness, headache, back pain, cold symptoms, jaundice (yellowing of the eyes or skin), skin rash, itching, and teeth or gum problems2.