The clinical efficacy of picotamide was investigated in a randomized, double-blind, placebo-controlled study in patients with peripheral occlusive arterial disease of the lower limbs at functional stage II of the Fontaine classification. Forty patients with a history of claudication for at least six months were admitted to the study and were given either 3 x 300 mg tablets of picotamide (20 subjects) or three identical placebo tablets (20 subjects) for six months. The two groups of patients were similar in regard to clinical features and potential risk factors. At the end of treatment painfree walking distance and systolic ankle-arm pressure ratio improved more in the picotamide than in the placebo group (p = 0.05). Systolic ankle pressure curves, determined before and after the six-month treatment, showed a positive trend to a higher postexercise ankle pressure and a faster return to the preexercise levels in the picotamide group; however, the difference was not statistically significant. Laboratory monitoring revealed a slight prolongation of bleeding time, a significant decrease in arachidonic acid-induced platelet aggregation, and an enhanced fibrinolysis with absence of interference with hemostasis in the picotamide group. One patient in the placebo group developed a major cardiovascular event (angina pectoris) during the study. These results indicate that picotamide is an effective drug that may modify the natural course of intermittent claudication and associated vascular problems.