The FDA recently increased the list of tainted weight loss pills from 29 to 69.. Three contaminants were listed

Sibutramine, which was found in many of the products, can cause high blood pressure, seizures, tachycardia (rapid heart beat), palpitations, heart attack or stroke.

Rimonabant, is associated with increased risk of depression and suicidal thoughts and has been linked to five deaths and 720 adverse reactions in Europe over the last two years.

Phenolphthalein a suspected cancer causing agent

If your on a weight loss supplement, you should see if it's on the FDA list

http://www.fda.gov/bbs/topics/NEWS/2008/NEW01933.html