A phase I/II study was conducted to determine the response rate and the toxicity of escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) plus cisplatin with granulocyte colony-stimulating factor support in patients with untreated advanced head and neck carcinoma. Twenty-eight patients with locally advanced inoperable squamous cell head and neck carcinoma were included. Median age was 51 years. Karnofsky performance status was > or =90% in all patients. Primary tumor sites were oropharynx, hypopharynx, larynx, oral cavity, parotid gland, nasal cavity, and unknown primary. We observed 13 complete responses, eight partial responses, four patients with stable disease, and two patients with progressive disease for an overall response rate of 78%. Toxicity was paresthesia grade 1/2 in 27 patients, and myalgias were grade 1/2 in 23 patients and grade 3 in four patients. One patient died 5 days after the first cycle due to acute renal failure, respiratory distress, and pancytopenia. No dose-limiting hematologic toxicity has been observed, and intrapatient escalations were performed in all patients when planned. Calculated dose intensity for the two drugs was 100% in all evaluable patients. The combination of escalating doses of paclitaxel 175 to 300 mg/m2 and cisplatin 75 mg/m2 was active in untreated head and neck carcinoma, with an overall response rate of 78%. No dose-limiting toxicity has been encountered at paclitaxel doses up to 300 mg/m2 given with granulocyte colony-stimulating factor.