The efficacy and safety of docetaxel in clinical trials in patients with a variety of malignancies are reviewed. The overall response rate for docetaxel as a first-line treatment for metastatic breast cancer is 59%. Docetaxel in combination with doxorubicin or vinorelbine has proved particularly effective in the first-line treatment of metastatic breast cancer. Docetaxel is also one of the most active single agents in the treatment of non-small-cell lung cancer (NSCLC), producing an overall response rate of 27% when used as a first-line agent. Docetaxel plus cisplatin was more effective against NSCLC than either drug used alone, yielding response rates of 33-48%. Docetaxel has shown activity against a variety of other tumors, including ovarian cancer (response rate in second-line therapy, 34%), head-and-neck cancer (response rate in first-line therapy, 35%), and soft-tissue sarcoma (response rate in first-line therapy, 32%). The main toxic effect is grade 3-4 neutropenia, which occurs in 57% of treatment cycles but is brief and manageable. The dosage of docetaxel should be reduced from 100 mg/m2 to 75 mg/m2 if patients have neutropenia lasting more than one week, febrile neutropenia, or impaired liver function. Other adverse effects include severe fluid retention and asthenia. Some adverse effects can be avoided by administering corticosteroid premedication. Docetaxel has shown efficacy against a wide range of cancers in clinical trials and has a manageable adverse-effect profile.