In a phase II study, the efficacy and toxicity of human recombinant tumor necrosis factor (rh TNF-alpha) were evaluated in patients with advanced colorectal carcinoma. Rh TNF-alpha was given as short term infusion at a dose of 3 x 10(5) U/m2 on three successive days. Treatment was repeated after a two week interval. The response was evaluated after four treatment cycles. In 15 patients entering the study, we found one partial response, one stable disease, 9 progressive diseases, and four patients who were not evaluable for tumor remission. There were numerous side effects of the treatment, mainly fever, chills, loss of appetite, leukopenia, and hepatotoxicity. In this regimen, rh TNF-alpha does not suggest a therapeutic advantage for treatment of advanced colorectal carcinoma.