This is the VOA Special English Health Report.

The United States Food and Drug Administration has ordered companies to place strong new warnings on thirteen drugs that treat sleep disorders. It also ordered the makers of the sleeping pills to provide information for patients explaining how to safely use the drugs.

Last Wednesday, the FDA announced that some of these drugs can have unexpected and dangerous effects. These include the risk of life-threatening allergic reactions. They also include rare incidents of strange behavior. These include people cooking food, eating and even driving while asleep. The patients later had no memory of doing these activities while asleep.

Last year, a member of the United States Congress said he had a sleep-driving incident. Patrick Kennedy, a representative from Rhode Island, crashed his car into a security barrier near the building where lawmakers meet. The accident happened in the middle of the night and no one was hurt. Mister Kennedy said he had earlier taken a sleep medicine. He said he was also being treated with a stomach sickness drug that can cause sleepiness.

The Food and Drug Administration did not say in its announcement how many cases of sleep-driving it has documented. However, the New York Times reported last year about people who said they had strange sleep events after taking the drug Ambien. Some reported sleep-driving and sleep-walking. Others said they found evidence after waking in the morning that they had cooked food or eaten in their sleep. But they had no memory of carrying out the activities.

A Food and Drug Administration official says that these serious side effects of sleep disorder drugs appear to be rare. But, he also said there are probably more cases than are reported. He said the agency believes the risk of such behaviors could be reduced if people take the drugs as directed and do not drink alcohol while taking the drugs. The Food and Drug Administration has advised drug companies to carry out studies to investigate the problem.

And that's the VOA Special English Health Report, written by Caty Weaver. Our reports and audio links can be found at WWW.51VOA.COM. You can send a health question to special@voanews.com. Please remember to include your name and country. I'm Steve Ember.