The aim of this study was to evaluate the clinical efficacy and safety of docetaxel (Taxotere) in patients with adenocarcinoma of the upper gastrointestinal tract previously untreated with cytotoxic chemotherapy. Docetaxel 100 mg m-2 was administered as a 1 hour intravenous (IV) infusion every 3 weeks to 41 patients. Patients were premedicated prior to each course with dexamethasone, diphenhydramine and cimetidine. Clinical response and toxicity were determined. Objective responses were seen in seven of 41 eligible patients (two complete responses [CRs] and five partial responses [PRs], for an objective response rate of 17% (90% confidence interval [CI], 8% to 30%). The most common toxicity was grade 4 neutropenia, which occurred in 88% of patients; 46% of patients required a dose reduction following an episode of neutropenic fever requiring antibiotic therapy. Additional patients have had reversible grade 3-4 toxicities including nausea, vomiting, stomatitis, diarrhea, fatigue and peripheral neuropathy. Ten patients have had grade 1-3 hypersensitivity reactions. Alopecia has been seen in the majority of patients. Fluid retention grade 1-3 has been observed in patients. Docetaxel administered on this schedule is an active agent in adenocarcinomas of the upper gastrointestinal tract. Further investigation of this drug should be conducted in multi-drug combination programs.