Clinically, most of the schizophrenics usually are treated with neuroleptics. This kind of medicine increases the prolactin level in serum that causes sexual dysfunction. In this study, 27 schizophrenics were divided into three groups. After discontinuation of taking the prior medicine for more than two weeks, subjects were treated respectively with fixed doses of haloperidol (20 mg), remoxipride (450 mg), and sulpiride (1800 mg). During hospitalization, an assigned senior resident used Nancy O. Andresen's Scale for the assessment of Positive Symptoms (SAPS) and Negative Symptoms (SANS) as tools to categorize schizophrenic subjects into subtypes, and another senior resident evaluated the effectiveness of the treatment once a week with the Brief Psychiatric Rating Scale (BPRS). Prolactin level in serum was monitored weekly with fluorescent assay. The Generalized Estimating Equation-I was utilized to analyze the data. The results show that all of the three medicines cause elevation of prolactin level in serum, and sulpiride causes the highest elevation of prolactin level in this study. There is no difference between the subtype of schizophrenia and prolactin reaction. There is also no correlation between the degree of elevation in prolactin and the effectiveness of treatment. However, there is a statistically significant difference in the serum levels between genders. After being treated with antipsychotics, female patients are more likely than male patients to have an elevated prolactin serum level. In conclusion, this study suggests that physicians should be more cautious while treating female psychotic patients with sulpiride.