Pure, natural sandalwood essential oil is safe for dogs and cats as long as it's applied in extremely diluted form, no more than 1 drop of sandalwood oil to 100 to 200 drops of product, such as pet shampoo, or carrier oil. There are approximately 100 drops in a teaspoon and 600 drops in an ounce, so the correct dilution ratio can be calculated from those figures. Never apply undiluted oil to a dog or cat. Pets may also be sensitive to any essential oils used in diffusers or as incense. Place these items in rooms not accessible to them.