Using an 'intelligent' tablet bottle which, unknown to the patient, electronically records the times of opening, we have assessed the compliance of patients with prescribed oral altretamine for ovarian cancer. During the periods of compliance monitoring the physical and mental state of the patients was also monitored by means of self-assessed diary cards. 11 patients were assessed over 21 monitoring periods, each of 14 days, representing a total of 294 days. The Overall Compliance (OC), which we define as the number of bottle openings in a monitoring period as a percentage of that number expected on the assumption of perfect compliance, had a mean (SD) of 97.4 (6.9)% over the 21 periods. The OC was not related to any of the diary card measures, or to the cycle number (range 1-5) of the treatment. The high level of compliance is encouraging and is in line with our previous reports in patients with lymphoma and with small cell lung cancer.