Discharge of oil after taking orlistat is a common adverse reaction after taking this medication. Orlistat is indicated for the reduction of risk factors associated with obesity, the reduction of the incidence of obesity-related diseases and obese patients. Orlistat works by inhibiting lipase activity, which reduces fat breakdown and absorption. Fat that cannot be broken down is excreted with metabolites, forming oily stools. In addition to the common oily stools, the adverse effects may include oily spots (i.e., seborrheic keratosis on the face), increased gastrointestinal emissions, frequent bowel movements, and fecal incontinence, etc. Depending on the amount of fat content of the meal, the symptoms of the adverse effects may be alleviated or aggravated accordingly. If the drug is stopped, the stools will slowly return to their original state. Special attention should be paid to the use of the drug strictly in accordance with medical advice, do not take it on your own.