Using human sunscreen on dogs is generally considered unsafe due to the high risk of ingestion. Dogs instinctively lick their skin, and many common ingredients in human formulations are highly toxic to them. Zinc oxide is a primary concern; if swallowed, it can lead to gastrointestinal distress and, in severe cases, life-threatening hemolytic anemia. Another common ingredient, salicylates (related to aspirin), can cause aspirin toxicity, leading to gastric ulcers and potential liver failure. Furthermore, the pH of human skin differs significantly from canine skin, meaning the chemical filters and fragrances used in human products can cause severe dermatitis or allergic reactions in pets. To protect your pet from UV rays, only use products specifically formulated for dogs. These products are free from these specific toxins and are safer if a small amount is licked off. Focus application on areas with thin hair, such as the nose and ears.