Misoprostol, the oral analogue of alprostadil, was used to treat 20 patients (aged 40-60 years) with peripheral arterial disease (PAD) according to Fontaine's classification at stages IIa and IIb. All patients received 200 micrograms of misoprostol 3 times a day during a month. The therapy with misoprostol resulted in clinical improvement in all patients. Elongation of pain-free (before treatment: 129 m +/- 78 m; after treatment: 214 m +/- 109 m) and maximum walking distance (before treatment: 304 m +/- 169 m; after treatment: 471 m +/- 264 m) was observed. At the same time, a shortening of the duration of pain was noted (before treatment: 100 sec +/- 37 sec; after treatment: 71 sec +/- 23 sec). The ankle/arm pressure ratio (AAPR) and arterial blood flow increased in both limbs after 4 weeks of treatment. Activation of the fibrinolytic system was seen in the course of therapy (shortening of euglobulin clot lysis time (ECLT) and increase in t-PA activity). The platelets became less sensitive to ADP and collagen after intake of misoprostol. The results justify administration of misoprostol as a new therapeutic agent for the treatment of patients with PAD.