Merville C. Marshall, Jr., M.D., F.A.C.P., F.A.C.E Responds:

Merville C. Marshall Jr., founder and president of the Endocrine Institute in White Plains, New York, responds: Clinical trials are often used to assess the effectiveness and safety of a new medication that is not yet on the market. Most clinical trials are randomized, placebo-controlled studies. This means that you may be given either the test medication or a placebo ("dummy" pill), and generally neither you nor your doctor will know which pill you are taking until the study is completed. 

You may benefit from participating in a trial if you actually receive the medication (rather than the placebo) and the medication proves to be effective. There can be other benefits: Access to a health care system and close monitoring of your condition are usually free of charge. Also, the knowledge gained from the study will benefit society at large. Of course, participation in a clinical trial is always voluntary, and you should be fully informed of any and all possible adverse effects. And always check with your doctor before signing up.