Fifty-three breast cancer patients receiving adjuvant chemotherapy entered a double-blind randomized trial of lorazepam 2.5 mg orally prior to chemotherapy and repeated after 12 hours (Arm A) versus placebo (Arm B) with methylprednisolone (MPN) 375 mg in 3 equal doses: 125 mg i.v. prior to chemotherapy and repeated i.m. 6 and 12 hours later. Adjuvant therapy with 5-fluorouracil 600 mg/m2, 4'-epi-doxorubicin 60 mg/m2, cyclophosphamide 600 mg/m2 (FEC) day 1 was alternated every 21 days with cyclophosphamide 600 mg/m2, methotrexate 40 mg/m2, 5-fluorouracil 600 mg/m2 (CMF) day 1 for a total of 12 courses. The majority of patients experienced greater than or equal to 5 emetic episodes with FEC therapy (Arm A = 52%; Arm B = 55%). Mild and moderate nausea were reported by 60% and 68% of patients in Arms A and B, respectively. With CMF therapy complete control of emesis was observed in 33% (Arm A) and 35% (Arm B) of patients. The addition of lorazepam did not improve results either with FEC or CMF. Sedation was experienced by 86 to 92% of patients treated with lorazepam and amnesia was observed in 48-50% of cases. FEC therapy must be considered a highly emetic regimen and antiemetic therapy planned accordingly.