Laser angioplasty for atheromatous plaque is a promising surgical technique for ablation of obstructing atheromas of the main arteries with restoration of the blood flow. This technique is based on visualization and laser vaporization of plaque through fiber optic catheters. Without specific staining, it is difficult to accurately visualize the plaque through an angioscope and to consequently optimize either the direction or duration of laser irradiation. Due primarily to lack of specificity or sensitivity or to toxicity, the current experimental dyes limit future growth of laser ablation of atheroma, a technique that appears to have outstanding potential as a routine and commonly performed surgical procedure if suitable stains can be found. In collaboration with Dr. Murphy-Chutorian of Stanford, Molecular Probes has started a program to synthesize and evaluate fluorescent target enhancement stains for plaque. Desired characteristics sought are: selectivity for staining plaque versus normal vessel wall, useful speed and duration of staining, sensitivity of detection, suitable spectral properties, ability to destroy plaque under laser irradiation, low toxicity and high stability and solubility. Preliminary experimental results using our dyes and literature studies indicate several promising materials. Future synthetic efforts will be directed to commercial development of the optimum dye for the staining.