Toxicity investigation of fenbendazole, an anthelmintic of swine

The toxicity of fenbendazole, an anthelmintic for use in swine, was tested by feeding 8 growing pigs 2,000 mg of fenbendazole/kg of body weight daily for 14 days. A transient leukopenia developed on day 6, but values returned to base line on day 18, 4 days after discontinuation of dosing. Sorbitol dehydrogenase values were significantly (P less than 0.05) increased from day 4 and returned to base line on day 20. Marked gross or histopathologic lesions were not found.