This study aimed at identifying the incidence of drug intake errors and the main therapy-related difficulties among AIDS patients as well as at proposing measures to increase patients' adherence to treatment. Sixty-one patients with AIDS assisted by the University Hospital of São Paulo State University at Campinas were interviewed. The most frequent errors concerned the combinations of drugs and the length of fasting. The difficulties reported were adverse effects and the variety of drugs. Based on these data, the authors proposed the use of an illustrated guide for drug-related information. It is hoped that individualized guidance can contribute to minimize errors concerning adherence to therapy.