In recent years the increased incidence of candidal infection is observed in the world, among them candidiasis takes the leading place. Candidiasis is an infectious disease caused by yeast-like fungi of Candida genus. There are both mild forms of this disease – candidiasis of the skin and mucous membranes and very severe forms – generalized candidiasis of visceral organs. In order to fight candidiasis the authors have developed an immunobiological drug for prevention and treatment of candidal infection. The drug contains antigens of C. albicans and C. tropicalis fungi with the total protein concentration of 4 mg/ml. The composition of the drug also includes the solvent phosphate buffer solution with рН 7.2 ± 0.2 and the preservative phenol in the concentration of 0.25 %. The drug developed possesses the protective and therapeutic effect. The aim of this work was to study toxicity of the immunobiological drug. The abnormal toxicity of the solution of the immunobiological drug for prevention and treatment of candidal infection was studied in two species of animals – mice and guinea pigs. To assess the toxic effect of the immunobiological drug solution on the animals’ organism the study of dynamics of the animals’ body weight was performed. The results obtained were compared to the body weight dynamics of the intact group that received the phosphate buffer solution. The animals were observed within 14 days. After the end of the observation period the autopsy and macroscopic examination of the animals’ internal organs were performed. During the autopsy when examining the internal organs of the animals the signs of intoxication or other manifestations of pathological processes were not revealed. To identify pathology the mass coefficients of the animals’ internal organs were determined. As a result of the research conducted it has been found that the immunobiological drug developed for prevention and treatment of candidal infection is atoxic.