A combination of cyclophosphamide, adriamycin, and cis-platinum (CAP) was tested in 20 previously untreated patients with locally advanced or metastatic breast cancer with the aim of assessing the ability of this platinum-containing regimen to induce a high complete remission rate. The drug regimen was given on a 3/week schedule at the following doses: cyclophosphamide 200 mg/m2 i.v. on days 1, 2, 3; adriamycin 40 mg/m2 i.v. or day 1 and cis-platinum 20 mg/m2 i.v. plus hydration on days 1, 2, 3. In the absence of progression, six cycles of CAP were planned and response was evaluated at that time. Thirteen of 20 patients achieved partial remission (65%) but only one obtained complete remission (5%). Overall median duration of response was 9 months (range 4-20 + months). Tumor response was mainly documented in soft tissues (primary tumor: 14 of 16; other sites: 19 of 20). Grade II leukopenia was documented in 60% of patients. All patients experienced moderate to severe gastrointestinal toxicity and alopecia was universal. No renal toxicity was observed. Although CAP regimen at the given dose schedule induced a high overall response rate (70%), the complete remission rate in this limited number of patients was lower than expected. These results do not appear superior to those achieved with conventional drug regimens.