No, dog owners should not give their dogs a slice of pizza. Pizza in general is not healthy for dogs. If the Pizza contains Pepperoni with garlic or onion powder, please do not feed it to your pooch. Some like to sprinkle garlic or onion powder onto their Pepperoni pizza.  Also, pizza contains cheese which is a dairy product. If your pooch is lactose-intolerant, he may experience an upset stomach or gastrointestinal upset. Keep in mind the type of oil that is used to make the pizza. If it is olive oil, then that is fine for doggy consumption.Overall, pizza is high in salt and fat. Regularly consuming fatty food can cause weight gain in dogs. For these reasons, it’s best to keep pizza away from your canine friends.