OBJECTIVES: I. Determine the efficacy of bryostatin 1 administered as a 24 hour intravenous infusion every week for 3 weeks during a 4 week course of therapy in patients with colorectal cancer. II. Determine the response duration, time to progression, and survival time in this patient population. III. Determine the qualitative and quantitative toxic effects of bryostatin 1 on this schedule in this patient population.