In the present work, we had tried to evaluate the immunotropic and behavioural effects of Thymus broussonetii Boiss. So, we tested the neurostimulant effects of four extracts. This preliminary study allowed to identify both the immunostimulant and the neurotropic antistress effects of the studied extracts. Among the four extracts, only the aqueous and ethyl acetate ones showed an apparent effect on the tested biological activities, whereas the butanolic extract and the essential oil did not show any interesting effect (data not shown). These results showed that the aqueous and ethyl extracts of this endemic species are of interest for two reasons: stimulation of the immunizing system and protection against the stress by a neurotropic activity. Thyme extracts increased in vivo the number of leucocyte categories studied including polynuclears, total lymphocytes, TCD4+, TCD8+ and NK cells. These data suggest that the intraperitoneal administration of Thymus broussonetii extract has a potent direct effect on leucocytes in vivo. The elevation of leucocyte and thrombocyte counts produced by thyme in the peripheral blood was already reported in the literature. These results could be of practical importance in the field of phytotherapy in the treatment of some cases of human immunodeficiency such as cancer, leukaemia and AIDS.