When Anita Louise Smith enrolled in an experimental drug trial in 2002 in Colorado, she had a diagnosis of multiple sclerosis but no symptoms and was looking to reduce the chances of being ravaged by the disease. Last year, she died at the age of 46 from an infection linked to the drug. This tragedy - recounted in an article in the March 4 issue of The Lancet by two Stanford University School of Medicine neurologists - serves as a telling case study of what can go wrong in clinical trials. In their article, Annette Langer-Gould, MD, and Lawrence Steinman, MD, warn of the pitfalls of testing a drug with unknown side effects in patients who would do fine without the drug.