In a single-blind, randomized trial, the efficacy of topical streptokinase-streptodornase (Varidase) solution was compared with that of zinc oxide on necrotic pressure ulcers in 28 patients. The effectiveness was determined by measuring the necrosis removal within 8 weeks. This occurred in 6 patients (43%) treated with Varidase and in 7 (50%) treated with zinc oxide. The statistical tests applied showed no significant difference between the two treatments despite the use of a high power (1-beta = 0.95). The data suggest that the two regimens are about equally effective in the treatment of necrotic tissue.