Excessive cigarette smoking and caffeine intake are often seen in schizophrenic patients being treated with antipsychotic drugs, particularly typical antipsychotic drugs. Using nicotine and caffeine sometimes influences psychotic symptoms in these patients. Clozapine is the only antipsychotic drug reported to reduce the amount of cigarette smoking, however, still remains controversial of its efficacy. In the present study, we examined the effect of acute risperidone treatment on the amount of cigarette smoking and plasma levels of cotinine and caffeine in schizophrenic patients. Treatment with risperidone for 4 weeks did not increase daily cigarette consumption or plasma levels of cotinine and caffeine. The results suggest that acute risperidone treatment does not promote the intake of nicotine and caffeine at least by 4 weeks in schizophrenic patients.