Orlistat helps you lose weight. May cause gas and even a oily discharge. Eating foods high in fat can make these side effects worse. Read all food labels and avoid foods that have more than 30% fat.

Orlistat Overview


Orlistat is a prescription and over the counter medication used for weight loss. Orlistat belongs to a group of drugs called lipase inhibitors, which work by preventing the absorption of fat in your body. 

This medication comes in capsule form and is taken up to 3 times daily with each fat-containing meal. 
Common side effects include oily spotting, stomach pain, and gas with oil or stool discharge.

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Orlistat Cautionary Labels


Uses of Orlistat

Orlistat is a medicine used to help obese people lose weight and keep this weight off. Orlistat should be used together with a reduced-calorie diet that your doctor will recommend. 

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information. 

Orlistat Brand Names

Orlistat may be found in some form under the following brand names:

Orlistat Drug Class

Orlistat is part of the drug class:

Side Effects of Orlistat

Because orlistat works by blocking the absorption of dietary fat, it is likely that you will experience some changes in bowel habits. These generally occur during the first weeks of treatment; however, they may continue throughout your use of orlistat.
These changes may include

  • oily spotting
  • gas with discharge
  • urgent need to go to the bathroom
  • oily or fatty stools 
  • an oily discharge
  • increased number of bowel movements
  • an inability to control bowel movements 
  • Due to the presence of undigested fat, the oil seen in a bowel movement may be clear or have a coloration such as orange or brown.

These bowel changes are a natural effect of blocking the fat from being absorbed and indicate that orlistat is working. They generally occur early in treatment, particularly after meals containing higher amounts of fat than are recommended. These symptoms are often temporary and may lessen or disappear as you continue treatment and keep to your recommended diet of meals containing no more than about 30% fat. However, these side effects may occur in some individuals over a period of 6 months or longer.

  • In obese adolescent patients treated with orlistat, the side effects reported were similar to those observed in adults.
  • If you are concerned about these or any other side effects you experience while taking orlistat, talk to your doctor or pharmacist.

Orlistat Interactions

Be sure to discuss with your doctor all medications (including herbal products) you are currently taking, including medicines you can get without a prescription (over-the-counter), to determine if orlistat can be taken in addition to these medications.

  • If you are taking cyclosporine, orlistat and cyclosporine should be taken at least 2 hours apart.
  • If your cyclosporine levels are being measured, more frequent monitoring may be necessary. 
  • If you are taking levothyroxine, orlistat and levothyroxine should be taken at least 4 hours apart.

Orlistat Precautions

You should not use orlistat if you:

  • consistently have problems absorbing food (chronic malabsorption); or
  • have gallbladder problems; or
  • are pregnant or are breastfeeding a child; or
  • have ever had an allergic reaction to orlistat or any of the inactive ingredients in orlistat

Orlistat has been shown to reduce the absorption of certain vitamins. You should take a multivitamin containing vitamins D, E, K, and beta-carotene once a day at least 2 hours before or after the administration of orlistat, such as at bedtime.

Some patients taking orlistat may develop an increased risk for the development of kidney stones. Promptly report any symptoms of back pain or blood in the urine.

Some patients prescribed orlistat may already be at increased risk for the formation of gall stones. Weight loss with orlistat can increase the risk of gall stones. Promptly report any symptoms of pain in the upper right portion of the abdomen. The pain may be accompanied by nausea and vomiting.

There have been rare reports of severe liver injury in patients taking orlistat. Promptly discontinue orlistat and contact your healthcare provider if you develop symptoms suggestive of liver impairment, such as loss of appetite, itching, yellowing of the skin, dark urine, light colored stools, or right upper quadrant pain.

Orlistat Food Interactions

You should use orlistat together with a nutritionally balanced, mildly reduced-calorie diet that contains no more than about 30% of calories from fat.

Read all food labels and avoid foods that have more than 30% fat.

Inform MD

Before beginning treatment with orlistat, make sure your doctor knows if you are:

  • allergic to any medicines, foods, or dyes
  • taking any other weight-loss medication
  • taking cyclosporine
  • taking thyroid medicine
  • taking any other medicines (including those not prescribed by your doctor)
  • taking any dietary supplements, including herbal products
  • planning to become pregnant
  • anorexic or bulimic

This information will help you and your physician decide if the expected advantages of orlistat are greater than any possible disadvantages.

Orlistat and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant. Orlistat should not be used during pregnancy as it may harm your unborn baby.

Weight loss offers no potential benefit to a pregnant woman and may result in fetal harm. A minimum weight gain, and no weight loss, is currently recommended for all pregnant women, including those who are already overweight or obese, due to the obligatory weight gain that occurs in maternal tissues during pregnancy. 

Orlistat and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if orlistat is excreted in human breast milk or if it will harm your nursing baby.

Orlistat Usage

  • Orlistat comes as a capsule to be taken with liquid at each main meal that contains fat.
  • You can take orlistat in conjunction with a mildly reduced-calorie diet up to 3 times a day.
  • Each time you take orlistat, your meal should contain no more than about 30% of calories from fat. 
  • Take orlistat during meals or up to one hour after a meal. If you occasionally miss a meal or have a meal without fat, you can omit your dose of orlistat. 
  • You should use orlistat together with a nutritionally balanced, mildly reduced-calorie diet that contains no more than about 30% of calories from fat. 
  • You should evenly divide your daily intake of fat, carbohydrates, and protein over 3 main meals.
  • You should try to follow a healthy eating plan such as the one developed by the American Heart Association. 
  • Following this eating plan will help you lose weight while decreasing some of the possible gastrointestinal effects you may experience while taking orlistat.

Orlistat Dosage

Take orlistat exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

Xenical (Prescription)

The recommended dose is one 120 mg capsule by mouth with liquid at each main meal that contains fat. You can take orlistat in conjunction with a mildly reduced-calorie diet up to 3 times a day.

  • Doses greater than 120 mg three times a day have not been shown to provide an additional weight loss benefit.
  • The use of orlistat for more than 4 years has not been studied. You and your doctor should discuss how long you should use orlistat.

Alli (Over the Counter)

The recommended dose is one 60 mg capsule by mouth with liquid at each main meal that contains fat. You can take orlistat in conjunction with a mildly reduced-calorie diet up to 3 times a day.

Orlistat Overdose

If you take too much orlistat, call your local Poison Control Center or seek emergency medical attention right away.

Other Requirements

  • Store at 20 - 25°C (68 - 77°F).
  • Keep this and all medicines out of the reach of children.
  • Protect drug from excessive light, humidity and temperatures over 30°C (86°F).