Despite the great progress in the treatment of pain, depression, anxiety, and other central nervous system (CNS) disorders, the used drugs do not fulfil all expectations. And there is still a need to search for new, more effective therapies as well as need to know the mechanisms of action of existing drugs. The tested compounds are a group of thiourea derivatives with expected potential central activity in the CNS. Numerous thiourea-derived compounds are selective ligands for 5-HT2 receptors family (Forbes et al. 1995) and also exhibit a broad spectrum of biological activities as analgesic, antidepressant, anticonvulsant, antiviral, anti-HIV, antibacterial, and HDL-elevating properties (Struga et al. 2007, Wardakhan et al. 2008, Karakus et al. 2009). Modification of the chemical structure makes it possible to obtain new compounds with pharmacological activity, higher selectivity and fewer adverse effects. Compounds were studied in behavioral tests used to predict a potential influence on the CNS in mice (after their ip or sc administration). The results of the pharmacological studies showed that new compounds exerted substantial impact on the CNS in mice. The most important seems to be their influence on the transmission of serotonin (activity in the head-twitch test, changes in body temperature) as well as antinociceptive effects. These compounds caused no coordination disorders, and do not affect locomotor activity, but slightly decreased the hyperactivity caused by administration of amphetamine. Obtained results indicate the possibility of the involvement of serotonin in the action of the majority of the compounds.