Mozzarella cheese is not toxic to cats, but it should be given only as an occasional, tiny treat and not as a regular part of their diet. Cats are obligate carnivores, so their meals should come mainly from high-quality meat- based cat foods. Many cats are lactose intolerant, and dairy products like mozzarella can cause digestive upset for those individuals. If you do decide to offer a small nibble, keep it plain (no added salt, garlic, onions, or other seasonings) and monitor for any stomach upset such as vomiting, diarrhea, or gas. Practical guidance

• Frequency: very rare and in tiny amounts (a crumb or two) as a special treat, not daily.
• Amount: a single, small piece is plenty; avoid large portions.
• Dairy tolerance: watch for signs of lactose intolerance (loose stools, gas, vomiting). If symptoms appear, stop feeding dairy.
• Alternatives: safer cat treats include commercially formulated cat treats or small bits of cooked, unseasoned chicken or tuna in water.

If you’d like, I can tailor guidance based on your cat’s age, weight, and known dairy tolerance, or help you choose cat-safe treat options.