Xenical, also marketed as Alli, is a medicine which reduces the colon's ability to absorb fat. The usual side effect is diarrhoea. These side effect are so severe that most patients do not accept them.

A medicine called Revia or Naltrexone, which was originally used for heroin addiction, can also reduce the problems of alcoholism and eating disorders. Some studies indicate that large doses are required for this effect. More.

Medicines like Prozac, Fontex and Seroscand (Fluoxetine) which raise the level of Serotonin can be a useful component in the treatment of compulsive eating.

1. They reduce hunger initially. This effect, however, disappears if you take them regularly for several weeks.
2. They normalise emotions. This effect will not show until after several weeks.

Reductil (Sibutramine, Meridia) is a similar medicine, where reduction of hunger is greater at the beginning of treatment. Also here, the effect diminishes with time. The risk for side efects like heart problems are so severe that this medicine has been stopped in most countries in the year 2009.

A medicine named Acomplia or Rimonabant will block a receptor for a cannabis-similar substance, which is part of the reward system in the brain. Sideeffects can be depressive symptoms, anxiety and disiness. When a patient quits using it, the weight will go up again. It is no longer permitted in many countries because of side effect risks.

It may sound surprising that medicines against obesity also can help non-obese people. But some people with eating disorders are very afraid of gaining weight. A medicine against over-eating can make them more secure, and thus allow a more normal eating.