Why
Kittens produce plenty of lactase, the enzyme that digests milk sugar, but most cats make much less of it as they wean and grow up. Lactose that is not digested pulls water into the gut and is fermented by bacteria, which leads to diarrhea, gas and sometimes vomiting. The Cornell Feline Health Center says milk is not generally recommended as a treat for cats, because many cats are lactose intolerant and can develop digestive problems from dairy.
Even cats that tolerate milk do not need it. Cats are obligate carnivores and get everything they need from a complete cat food and fresh water. Cow's milk adds fat and calories, and many indoor cats are already prone to gaining weight.
Risks to watch for
- Diarrhea or soft stools, often within about 12 hours
- Vomiting
- Gas and an uncomfortable, bloated belly
- Weight gain if milk becomes a daily habit
- Dehydration if vomiting or diarrhea is severe or lasts more than a day
How to share safely
- Fresh water is the only drink an adult cat needs. Milk should never replace it.
- If you choose to share, offer no more than a teaspoon of plain milk and watch for stomach upset over the next day.
- Lactose-reduced milks made for cats are gentler on the stomach, but they still add calories, so count them as treats.
- Never give chocolate milk, sweetened or flavored milk, or cream-based drinks.
- Orphaned or underweight kittens need a commercial kitten milk replacer and help from a vet, not cow's, goat's or plant milk.
How much?
For an adult cat that clearly tolerates it, PetMD's veterinary guide suggests that a teaspoon once or twice a week is unlikely to do harm. Many cats are better off with none.
Why do cats love milk if it upsets their stomach?
Many cats clearly enjoy the taste of milk and cream, and the picture of a cat with a saucer of milk is an old one in storybooks and cartoons. Liking a food does not mean the gut can handle it. A cat that laps up milk happily can still have loose stools a few hours later, and owners do not always connect the two.
If your cat begs for milk, a teaspoon of lactose-reduced cat milk, a little extra water mixed into wet food, or a pet water fountain can give it something new to drink without the stomach upset.
What should a kitten drink?
Kittens are born able to digest their mother's milk and lose much of that ability as they wean, usually by around 8 weeks of age. Until then, the right substitute for a missing mother is a commercial kitten milk replacer made to resemble cat milk. Cow's, goat's and sheep's milk have a different balance of nutrients, and replacers made for puppies are not suitable either.
Bottle-feeding a very young kitten involves more than the right formula. Warmth, a regular feeding schedule and help with going to the toilet all matter, so ask a vet or an experienced rescue group for guidance.
Cream, cheese, yogurt and plant milks
Cream has even more fat than milk, and fat alone can cause vomiting or diarrhea in cats that are not used to it. Hard cheese and plain yogurt usually contain less lactose than milk, but they are still dairy and should only ever be tiny, occasional treats.
Plant milks are not a better substitute. Oat, soy, almond and coconut milks can be high in fat, may contain sugar, oils, thickeners or salt, and offer nothing a cat needs.
Common questions
Is milk good for cats?
Only in limited ways. Kittens produce plenty of lactase, the enzyme that digests milk sugar, but most cats make much less of it as they wean and grow up. Lactose that is not digested pulls water into the gut and is fermented by bacteria, which leads to diarrhea, gas and sometimes vomiting.
Is milk bad for cats?
It can be. Risks to watch for: diarrhea or soft stools, often within about 12 hours; vomiting.
Are cats allowed to have milk?
Only in small amounts and the right form. Fresh water is the only drink an adult cat needs. Milk should never replace it.
Is lactose-free milk safe for cats?
Lactose-free cow's milk removes the main cause of diarrhea, so it is gentler than regular milk. It still has the same fat and calories, so treat it as a small, occasional treat, not a drink.
Can cats drink goat's milk?
Goat's milk still contains lactose, so a cat that reacts to cow's milk may react to goat's milk too. It is not a substitute for kitten milk replacer.
Should I give milk to a cat that has eaten something poisonous?
No. Milk does not neutralize poisons and can add to stomach upset. Call your vet or a poison control service instead and follow their instructions.
Sources
- PetMD. Can Cats Drink Milk? (Sandra C. Mitchell, DVM, DABVP)
- ASPCA Animal Poison Control Center. People Foods to Avoid Feeding Your Pets.
- Cornell Feline Health Center. Feeding Your Cat.
If your cat has eaten something toxic, contact your veterinarian, an emergency animal hospital or an animal poison control service right away, even if your cat seems fine. Do not try to make your cat vomit at home.