Pizotifen (BC-105) is a potent 5-HT₂ receptor antagonist, with a high affinity for 5-HT_1C binding site. In Vitro: Pizotifen (BC-105) is a potent 5-HT₂ receptor antagonist, with a high affinity for 5-HT_1C binding site^[1]. Pizotifen is an antidepresent 5-HT_2A receptor antagonist and has the capacity to inhibit serotonin-enhanced ADP-induced platelet aggregation^[2]. In Vivo: The weights of the fetuses are significantly reduced by all administered doses of Pipethiadene and Pizotifen (BC-105); the weights of the placentas are significantly reduced after 0.6 and 1.2 mg/kg Pipethiadene and only after the middle dose of Pizotifen. The means of the implantations, live, dead fetuses, resorptions and the occurrence of external, skeletal and visceral anomalies do not differ from the control group. The number of chromosome aberrations in the bone marrow cells of treated mice does not differ significantly from the negative control group. The micronucleus test reveals no elevation in the frequency of micronuclei as compared to the control group. After the two higher doses of both Pipethiadene and Pizotifen (BC-105) maleate, the mitotic indices are lower than in the control group^[3].