Two dogs were referred due to vomiting, depression and anorexia after ingestion of xylitol gum. Both dogs were presented with hepatic failure and one dog had concurrent renal failure. Aggressive supportive treatment was performed, but these dogs died. Necropsy of one dog revealed acute hepatic necrosis, severe renal damages, and hemoperitoneum. This case report demonstrates potential hazard of xylitol toxicity for dogs with clinicopathological and pathological findings.