Psychiatric disorders affect a high percentage of the world`s population. Schizophrenia represents more than 90% of the inpatients
of mental health hospitals. Risperidone is an important drug in the treatment schizophrenia. The study was designed to assess
efficiency of Costus extract in limiting side effects occur as a result of the use of risperidone. Rats were divided into six groups G1
control animals. G2 treated with Costus extract. G3+5 treated with risperidone at low & high doses. G4 +6 treated with both
risperidone at two dose and Costus extract. Bioassay results of blood`s rat in G3,5 showed below-average levels of testosterone,
high average levels in rat in G2,G4,G6. Histological and ultrastructural observations in testes of rats in G3, 5 showed: atrophy of
several seminal tubules, necrosis of spermatogenic cells, pyknotic nuclei and loss of sperms. Rat in G4, 6 showed: Seminiferous
tubules had a regular architecture more or less similar to control. Risperidone induced increase of CYP3A, CYP2E1, CYP2C6 and a
decrease of CYP1A1 levels of P450 In testis. High-dose risperidone with Costus induced a decrease of all previs gene levels. Costus
extract was raising the efficiency of fertility in the testes of male rats treated with risperidone.
Keywords: costus extract, risperidone, testis, ultrastructural, molecular, fertility