Yes. Most adult cats are lactose intolerant, meaning they lack the enzyme needed to digest milk sugar (lactose). Drinking regular cow’s milk typically causes stomach upset, gas or diarrhoea. A small amount of lactose-free milk or specially formulated cat milk can be fine as an occasional treat, but clean water and a balanced diet should be their main sources of hydration.
In This Article:
Why Do Cats Drink Milk if It’s Not Good for Them?
Milk has a rich, fatty aroma that cats find appealing. Kittens associate it with nursing, and the high fat content appeals to adult cats. However, this doesn’t mean it’s good for them.
Can Cats Drink Cow’s Milk? Is Milk Bad for Cats?
Regular cow’s milk is not recommended for cats. It contains high levels of lactose, which most cats can’t digest. Cow’s milk offers no benefit to adult cats and is likely to cause digestive upset. It’s best to keep cats on cat food and water only, unless a vet specifically advises otherwise.
Should I Give My Cat Milk (Even Occasionally)?
Even as an occasional treat, cow’s milk is not a smart choice for most cats. Once kittens are fully weaned (around 6–8 weeks old), they should be drinking water, not milk.
That said, there are cat-safe milk drinks on the market. These are real milk products processed to remove almost all lactose. A few tablespoons once in a while is fine as a treat, but it should never replace water or a proper meal and remember to always count it as part of your cat’s daily calories.
Can Cats Drink Lactose-Free Milk?
Lactose-free cow’s milk (sold for humans with lactose intolerance) has had the lactose sugar broken down. This means it won’t upset most cats’ stomachs. We usually advise a small saucer of lactose-free milk can be given as an occasional treat, however, the key is moderation. Lactose-free milk adds calories but no real nutrients for cats – it’s essentially water with some fat and protein.
What About Cat-Specific Milk and Goat’s Milk?
You may find commercial “cat milk” products (e.g. Whiskas Catmilk). These are made from dairy but processed so ~98–99% of lactose is removed. Because of this, most cats digest them without problem. They also often contain added vitamins and are marketed as a treat or supplement.
However, cat milk products are still very calorie-dense. They contain almost as much fat and sugar as regular milk. Think of them like a small snack. A few tablespoons on a rare occasion is unlikely to hurt a healthy cat, but they should not be a daily habit.
Goat’s milk: Goat’s milk has slightly less lactose and extra enzymes, and many cats enjoy it. It even contains beneficial vitamins and probiotics. However, goat’s milk still contains lactose. If a cat reacts badly to cow’s milk, goat’s milk can still cause an upset.
Are Plant-Based “Milks” Safe for Cats?
What about soy, almond, oat, or other plant-based milks? Most pet experts advise against these. Although they have no lactose, cats are carnivores and have not well adapted to these substitutes. For example:
- Soy milk: Soy milk contains phytates that can block nutrient absorption, and cats can’t digest soy proteins well. Large amounts of soy in their diet can harm a cat’s liver in extreme cases.
- Almond, coconut, oat milks: These often contain high levels of fat or other additives. They also often contain sugar or thickeners that cats shouldn’t have.
- Sweeteners/additives: Many plant milks are sweetened or flavoured, which is junk food for cats.
Bottom line: Plant “milks” offer no nutritional benefit to cats and may cause digestive problems. We advise sticking to water and cat-formulated foods.
Signs Your Cat Can’t Handle Milk
If you can’t resist the sad puppy eyes your cat is giving you and cave, watch for these signs of lactose intolerance:
- Diarrhoea or loose stool, often within hours.
- Vomiting soon after drinking milk.
- Gas or bloating – you may notice a smelly, gassy stool.
- Abdominal discomfort: the cat might become lethargic or sit hunched over.
- Reduced appetite or lethargy – if they feel unwell, they may not eat or play.
How to Test if Your Cat Is Lactose Intolerant
If you’re curious whether your cat is truly lactose intolerant, you can test carefully:
- Give a tiny amount: Offer only a teaspoon of milk (cow, lactose-free, or cat milk).
- Observe: Monitor your cat closely for 6–12 hours for any changes.
- Check the litter tray: Look for loose stool or signs of gastrointestinal upset after 8–12 hours.
If your cat develops diarrhoea or vomits, they are intolerant to the milk given. If no symptoms appear, your cat can probably tolerate a very small amount. However, even if your cat seems fine, do not make milk a regular part of the diet.
Hydration Tips (Milk-Free)
Cats should get their hydration from water and wet food, not milk. To keep them well-hydrated:
- Fresh Water: Always provide clean water in a wide, shallow bowl. Change it daily.
- Multiple Sources: Place water bowls in several locations to encourage sipping.
- Water Fountain: Many cats prefer running water. A cat water fountain can significantly increase intake.
- Wet (Canned) Food: Offer high-quality wet cat food. It’s ~70–80% water and greatly boosts hydration.
- Broth Flavouring: Drizzle a little unsalted chicken or tuna broth into their water or food to make it more appealing.
- Mix with Food: Add a bit of warm water to dry kibble before serving.
Reminder: Do not use milk as a water substitute. The best drink for cats is pure water. All the above tips help ensure your cat stays hydrated without any milk.
What Do Cats Drink, Really?
As pets, cats thrive on fresh water and moist cat food. A balanced cat diet with plenty of wet food will provide needed fluids and nutrients. See our guide How much wet cat food should I feed my cat? for feeding guidelines.
Be cautious about any human food or drink. Avoid giving cats any caffeinated, alcoholic, or heavily sweetened drinks. For a list of safe snacks and foods, check our guide What human food can cats eat & what to avoid.
Conclusion
The short answer is: Milk is not a necessary part of a cat’s diet. In fact, it’s often a problem. Nearly all adult cats are lactose intolerant. Giving a cat cow’s milk will usually lead to digestive upset, and it can contribute to obesity because of its high fat and calorie content. If your cat really loves milk, you may allow a tiny taste of lactose-free or special cat milk as an occasional treat, but make sure fresh water is always available.
If you ever have concerns, consult a vet. Any drastic change in diet (like adding milk) should be discussed, especially for cats with health issues. But in general, keep cats hydrated and healthy with water and proper cat food, not milk.
FAQs:
Are all cats lactose intolerant?
Almost all adult cats have reduced lactase enzyme after weaning. So yes, most grown cats are lactose intolerant to some degree. Kittens can digest their mother’s milk, but their ability to handle milk drops off quickly as they grow.
My cat drinks milk with no issues. Is it OK?
If your cat truly shows no symptoms (no vomiting, diarrhoea, or gas) after a small amount of milk, then an occasional teaspoon might not hurt. However, this should be very rare. Many cats tolerate a little while young, but eventually will have trouble. Always monitor them after giving milk.
Can kittens drink cow’s milk?
No. Kittens should only drink their mother’s milk or a kitten-formula replacer. Cow’s milk does not have the right balance of nutrients and is too high in lactose, which can upset a kitten’s stomach once it starts weaning.
Is lactose-free or soy milk safe for cats?
Lactose-free milk: Generally safe in tiny amounts as a treat, since it won’t upset lactose intolerance. But it’s still just extra calories. Soy/almond/other milks: Not recommended. Cats can’t digest soy properly and often react badly to plant milks.
What should I give my cat if it won’t drink water?
Encourage water with methods like a fountain, ice cubes, or unsalted broth. Offer wet food for extra moisture. If the cat still refuses all water, consult a vet – cats can dehydrate quickly. But never use milk as a substitute for water.
Is goat’s milk better than cow’s milk for cats?
Goat’s milk has slightly less lactose and more nutrients, so some cats may handle it better. But it still contains lactose, so it can still cause upset in lactose-intolerant cats. It’s also high in fat. In practice, goat’s milk is only a marginally gentler option and should still be given very sparingly.
What can cats drink instead of milk?
The best drink for cats is pure water. They also get water from wet cat food. Unsalted broths or special cat “milks” can be given rarely, but fresh water should be the default.
