Carotid intima-media thickness is used by drug companies to evaluate the efficacy of new cholesterol lowereing medications. In the last 5 years, dramatic findings haev been made using IMT as an outcome variable. The most recent and dramatic case in the United States was the evaluation of Vytorin, a combination cholesterol lowering medication. Merck. The lack of drug efficacy, as documented by carotid IMT, had large financial impact as well as changed prescription patterns dramatically. This presentation with review the protocols used inn drug trials and show the technical hurdles that have to be overcome before carotid IMT can be a reliable clinical tool.