Orlistat is mainly used to reduce caloric intake and control weight, and is mainly used to treat people who are obese or overweight. Orlistat can only be used for obese people with a body mass index greater than or equal to 24. It should not be used for patients with a body mass index less than 24, and is contraindicated for pregnant women. If a meal contains fat, it is best to take the drug before, during and within one hour after the meal. Orlistat may cause serious liver damage. Liver function tests are needed if you experience loss of appetite, itching, dark urine, light stool color, and right upper abdominal pain after taking the drug. Orlistat will also reduce the absorption of fat-soluble vitamins. A multivitamin should be taken once a day during the medication period, either 2 hours after taking Orlistat or just before going to bed.