Cohorts of 3-6 patients in each schedule receive escalating doses of edotecarin until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. Once the MTD is determined, 10 additional patients with metastatic esophageal or gastric cancer receive treatment as above at the MTD.