Generally, Orlistat can take effect 24~48 hours after taking it. Orlistat belongs to the gastrointestinal lipase inhibitors, which can play a role in inhibiting the hydrolysis of triglycerides to achieve the purpose of reducing calorie intake and weight control, and can be used for the treatment of overweight or obese patients. It is contraindicated in people who are allergic to orlistat or any of the components of the drug preparation, pregnant women, patients with organic obesity (e.g. hypothyroidism), chronic malabsorption syndrome, cholestasis. Usually, the effect of the drug can be seen 24-48 hours after the use of the drug, and after the use of the drug may be fat diarrhea, increased gastrointestinal excretion, increased frequency of stools, fecal incontinence and other adverse reactions. Patients who need to take orlistat for treatment should use the drug under the supervision of a doctor.