RH-5849 (Toxicology Department Sample Number 87-172; lot no. WCT 2351, 99.6% active ingredient) was administered to 5 groups (4 dogs/sex/group) of Beagle dogs LRE Inc., Kalamazoo, MI, for 3 months at dietary concentrations of 0 (control), 10, 100, 400, and 1200 ppm of active ingredient (a.i.). All dogs were observed daily for signs of ill health or reaction to treatment and physical examinations were performed weekly. Feed consumption was monitored daily and body weights were monitored weekly beginning 2 weeks prior to treatment. Twice during the pre-test period and at 1 and 3 months after compound administra- tion, all dogs were bled for hematology and clinical chemistry analysis. Urinalysis, neurology, and ophthalmology examinations were performed on all dogs during the pre-test period and at week 13 of compound administration. At the end of 3 months of treatment, all dogs were killed, necropsied, selected organ weights recorded, and tissues collected for histological evaluation.