One hundred thirty-eight patients with primary syphillis and 161 patients with secondary syphilis were treated with penicillin G benzathine, 2.4 million units given intramuscularly weekly for two weeks, for a total of 4.8 million units. All 138 patients with primary syphilis had a rapid resolution of their lesions, and all became seronegative within one year. Similarly, the 161 patients with secondary syphilis were cured clinically, and all achieved seronegativity within 24 months.