Laser angioplasty is used to vaporize atheroma in limb arteries. The present investigation was undertaken to determine the nature, size and quantity of particulate matter generated, and the appearance of the intima of a carotid artery model after laser treatment. Particulate matter was not significantly increased following treatment of 39 autopsy carotid bifurcations, but superficial plaques were vaporized and the surface of fibrous lesions glazed. It is anticipated that atheromatous carotid vessels would be rendered less thromobogenic and the risk of cerebral embolism reduced later angioplasty.