Taxol (Bristol-Meyers Squibb) is active against carcinomas of the ovary, breast, lung, esophagus and head and neck. A number of dose schedules of Taxol have been tested in breast cancer. Initial trials used 250 mg/m2 as a continuous infusion over 24 hours. Subsequently, shorter infusions of Taxol over three hours were tested at a dose of 175 mg/m2, with response rates of 30%-40%. Phase II studies using higher doses of Taxol at 200-250 mg/m2 had a response rate of 56% in metastatic breast cancer patients. However, at these doses, significant toxicities occurred, including neuropathy. There was a median granulocyte count nadir at 100-200 cells/mm3 for the majority of courses administered. There were also significant side effects associated with hypersensitivity to the Taxol vehicle, Cremophor-EL. These hypersensitivity reactions require a premedication schedule that includes a corticosteroid, an H2 antagonist and an antihistamine.