The first U.S. non-prescription weight loss pill was approved this week by U.S. health officials.

The drug, whose generic name is orlistat, was approved for prescription use in cases of obesity by the U.S. Food and Drug Administration in 1999. It will be produced and marketed by manufacturer GlaxoSmithKline under the name Alli, the FDA said Wednesday.

We know that being overweight has many adverse consequences, including an increase in the risk of heart disease and type 2 diabetes, said Dr. Douglas Throckmorton, Deputy Director for FDA's Center for Drug Evaluation and Research. OTC orlistat, along with diet and exercise, may aid overweight adults who seek to lose excess weight to improve their health.

The pill helps users lose weight by decreasing the body's absorption of fat. The FDA says those who are not overweight or who have problems absorbing food should not take the drug.

Among the common side effects are loose stools, the agency said. However, eating a low-fat diet can lower the likelihood of that effect. Those who have had organ transplants should not take the drug.

Also, anyone taking blood thinning medicines, and those being treated for diabetes and thyroid disease should speak to their doctors before using the drug.

Other products, which carry a higher dosage of orlistat than Glaxo's Alli product will still require prescriptions.

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