Which of the following is a common side effect of Orlistat?

• A. Weight gain
• B. Diarrhea
• C. Steatorrhea
• D. Nausea

Answer: (C)

Orlistat works by blocking pancreatic lipase in the gut, so fat from the diet isn’t digested and absorbed. The undigested fat then passes into the stool, causing steatorrhea—fatty, oily, bulky stools that may float or have a foul odor. This is the characteristic and common side effect you’d expect with this medication, especially when eating higher-fat meals. Weight gain isn’t typical since the drug’s goal is to reduce fat absorption, and nausea can occur but is less specific. To help limit steatorrhea, people often adopt a lower-fat diet and consider fat-soluble vitamin supplementation since fat absorption is reduced.