The incidence and severity of toxicity, the extent of emotional disturbance and cost of adjuvant chemotherapy were assessed in patients with early breast cancer randomized to receive either radiotherapy, chemotherapy (CMF) or radiotherapy followed by chemotherapy. Nausea and vomiting occurred in 85 per cent of patients receiving chemotherapy and contributed significantly to distress. Over one-third of patients required a wig or developed mucosal ulceration. Nevertheless, most patients were able to return to work during treatment. Leucopoenia was more commonly encountered in those patients who received radiotherapy prior to chemotherapy. Twelve months after mastectomy, psychiatric morbidity was present in 13 of 34 patients receiving chemotherapy with or without radiotherapy, compared with only 1 of 18 receiving radiotherapy alone. Anxiety was common in both groups. This trend was still present 6 months after the completion of chemotherapy. The cost of chemotherapy is discussed.