There have been anecdotal reports that local hyperthermia was effective in the treatment of viral warts. We conducted a randomized, patient-blinded, placebo-controlled trial to test the effect of local hyperthermia (44 degrees C for 30 min a day for 3 consecutive days plus 2 additional days 2 weeks later) on plantar warts. By the end of 3 months, 53.57% of patients (15/28) in the treatment group and 11.54% of patients (3/26) in the control group were cured (P < .01). The effect was not influenced by patient age, duration of disease, or number or size of lesions.