The aim of the present study was to assess the antiemetic efficacy of granisetron in repeated cycles of chemotherapy with platinum derivatives. The study included 50 patients (28 females, 22 males; aged 17-72, mean age 51 years). From 2 to 5 cycles of chemotherapy with cisplatin or carboplatin were performed. Granisetron was administered intravenously at a dose of 3 mg, 5 minutes before commencement of cytostatic chemotherapy. In case of 2 episodes of vomiting and severe nausea 2 additional doses of granisetron were given. Total control of emesis was achieved in 60% of patients after the first cycle of chemotherapy, and this percentage did not change significantly over the 5 cycles of chemotherapy. There were no differences in the antiemetic efficacy of granisetron in relation to patient sex up to cycle III, while in cycles IV and V a tendency towards less efficacy in females was observed. The adverse effects (headache, dizziness) were observed with the same frequency in the first 3 cycles of chemotherapy, while these were absent in cycles IV and V. Severe side effects were recorded only in cycle I, after that they were less expressed. In conclusion, granisetron is highly effective in prevention of emesis, induced by platinum derivatives and its efficacy is maintained over repeated cycles of chemotherapy. The toxicity of granisetron is mostly expressed in the first cycle, while after that it decreases significantly.