Toxoplasmosis which is caused by Toxoplasma gondii, has a high risk of fetal infection development if the infection occurs during pregnancy. Treatment with oral spiramycin is recommended during pregnancy in order to prevent the transmission of protozoa to fetus and development of infection. Since beta-glucan is known to stimulate the immune system and increase the phagocytic activity of the cells, it has been shown to exhibit immunomodulatory effect on many infectious diseases. The objectives of this study were to investigate the effectiveness of beta-glucan alone and in combination with spiramycin and to determinate the levels of interlokin (IL)-10, IL-12 and tumor nekrosis factor (TNF)-alpha in mice experimentally infected with T.gondii. For this purpose, four experimental groups each consisting of eight BALB/c mice, were formed with the approval of Ethics Committee for the Animal Experiments. All the mice were infected with 2 ml of suspension containing 2 x 10(2)/ml of trophozoite prepared from T.gondii RH strain (Refik Saydam National Public Health Agency, Parasitology Laboratory of Communicable Diseases Research Department, Ankara, Turkey), by intraperitoneal injection. Twenty-four hours after the infection, beta-glucan (3 mg/day) was given to the beta-glucan group, spiramycin (200 mg/kg/day) to the spiramycin group, beta-glucan (3 mg/day) plus spiramycin (200 mg/kg/day) to the beta-glucan-spiramycin (BG-S) group by oral gavage. The fourth group which was the control group was infected but untreated. The above administration was carried out for seven days. On the 8th day, under anaesthesia, 1 ml normal saline was given into the peritoneum, drawn back later and the number of trophozoites in 1 ml of peritoneal fluid was determined by counting them on the Thoma slide. Moreover, by drawing the heart blood; IL-10, IL-12, TNF-alpha levels were determined in serum samples by ELISA method (eBioscience Platinum, Austria). The number of trophozoites in the BC-S group was found significantly lower than the number of trophozoites in control, beta-glucan and spiramycin groups (p<0.05). There was no significant difference between the beta-glucan and spiramycin groups, however the number of trophozoites in both groups was significantly lower than the number of trophozoites in the control group (p<0.05). There was a certain decrease in IL-10 level in spiramycin and BC-S groups, compared to the control group, in addition when IL-10 levels in spiramycin and BC-S groups were compared with BC group, a significant decrease was noticed (p<0.05). There was no difference in IL-12 levels between the groups, while there was a certain decrease in TNF-alpha level in beta-glucan, spiramycin, BC-S group in comparison to the control group. Within the reach of our literature survey, this study is the first research in which the effectiveness of the combination of beta-glucan and spiramycin in the treatment of acute toxoplasmosis was investigated. The results of our study suggested that there might be synergy between beta-glucan and spiramycin in the treatment of acute toxoplasmosis.