A double blind placebo-controlled randomised crossover study was performed with Pentoxifylline (Trental 400 tablets with 400 mg active ingredient) in 24 patients (19 males, 5 females, aged between 40 and 71 years) suffering from peripheral occlusive arteriopathy of stage II severity (Fontaine's classification). In 12 patients (group I) the treatment was started with placebo, and in another 12 subjects with Pentoxifylline (group II). The dosage was 3 tablets of either formulation t.d.s., the treatment periods were 8 weeks each with a two week washout between. The standardised walking test (120 steps/min under metronome control) was used for the assessment of the walking capacity. There was a significant 60% increase in pain-free walking distance in either Pentoxifylline treatment periods, whereas there were no clinically relevant changes in the placebo periods. When comparing the two starting periods only, there was an increase in the Pentoxifylline group from 223 to 359 m on average and in the placebo group from 208 to 215 m, patients in both groups being comparable at basal level as to the distribution of sex, age, location of occlusion, duration of disease as well as in respect to the walking capacity. No adverse reactions were recorded during the trial.