The purpose of the research is to evaluate some toxicological parameters of a new combined anthelmintic based on oxantel pamoate, pyrantel pamoate and praziquantel in tablet formulation for dogs and cats.Materials and methods. The studies used 70 outbred male rats and 50 outbred male mice. Acute oral toxicity was studied in male mice and male rats weighing 14–16 and 160–180 g, respectively. The subchronic toxicity study with the drug administered repeatedly, orally for 14 days was conducted on male rats weighing 180–200 g. The study monitored the laboratory animals’ overall health status, behavior and possible death, and any intoxication symptoms were recorded. All studies were performed using conventional techniques for experimental (preclinical) studies of new pharmacological substances using the guidelines edited by R. U. Khabriev (2005) and A. I. Mironov et al. (2012). Additionally, the experiments assessed clinical toxicological, biochemical, and morphological parameters of the laboratory animals.Results and discussion. In evaluation of the drug acute toxicity in the male mice and the female rats, the LD50 exceeded the dose of 6000 mg/kg; the animals showed no signs of intoxication during the entire study. Thus, the drug was classified as substance hazard category 4. Doses 600, 300 and 120 mg/kg of the drug had no negative effect on the organism of the laboratory animals in the subchronic experiment on the male rats; the doses were ineffective (safe). The threshold or toxic dose could not be determined.