Docetaxel and gemcitabine have been shown to be active as single agents in a variety of solid tumors. These two agents have been studied in combination with several different treatment schedules. Two phase I studies used a novel 2-week administration schedule that involved a 1-hour infusion of 35 mg/m2 to 65 mg/m2 docetaxel and gemcitabine administered as either a 30-minute infusion (2,000 to 4,000 mg/m2) or a 10 mg/m2/min infusion (1,000 to 1,200 mg/m2 total dose). Another novel phase I study evaluated the effect of drug sequence on toxicities. Patients received 30 to 40 mg/m2 docetaxel and 800 to 1,250 mg/m2 gemcitabine on days 1 and 8 every 21 days. Two phase I studies of a monthly docetaxel regimen have been conducted. Patients received 800 mg/m2 gemcitabine on days 1, 8, and 15 and 100 mg/m2 docetaxel on day 1 of a 28-day cycle. Finally, in a phase II study, patients received 900 mg/m2 gemcitabine on days 1 and 8 and 100 mg/m2 docetaxel on day 8, with granulocyte colony-stimulating factor administered on days 9 through 15. In these studies, antitumor responses were observed in lung cancer as well as a number of other histologies. Neutropenia was the most frequent dose-limiting toxicity and no difference in clinical toxicity was observed with either sequence of administration. The emerging evidence suggests, therefore, that the combination of gemcitabine and docetaxel is active in a variety of solid tumors and is well tolerated.