The buccal administration of streptokinasestreptodornase was tried in the treatment of a test group of 52 patients who had superficial thrombophlebitis as a complication after venoclysis. A contratest group of 22 patients, who received general treatment but neither the drugs nor a placebo, were observed for comparison. The investigator who evaluated the progress of the two groups did not know, in most instances, to which group a given patient belonged. The streptokinasestreptodornase was given either as one tablet (10,000 units) four times daily or two tablets every four hours; the tablet was kept in the patient's mouth until dissolved. Under these conditions no significant difference between the two groups was found, and no evidence of therapeutic or prophylactic action was obtained.