Can my cat drink milk?
Cats and milk go together like…well, they really shouldn’t go together at all.
The image of a cat lapping at a saucer of milk is ingrained in our shared cultural notions about cats. I actually designed a giant cardboard playhouse for cats that looks like a container of milk for this very reason.
But that doesn’t mean cats should drink milk.
Let’s discuss how this idea about cats and milk came to be, and why your cats should drink something else.
Do cats like milk?
Many, but not all, cats seem to absolutely crave milk. Why?
In 1977, some scientists studied the flavor preferences of cats and found out cats like the taste of protein and fat. They actually preferred to drink straight butterfat dissolved in water to just plain old milk.
Numerous studies on human health suggest that we, too, have a similar drive to find and consume fatty foods, presumably to keep up with the metabolic demands of our large brains. I’ll admit to overdoing it at times.
One review of the science around cats and their appetite for milk questioned whether cats’ enjoyment of milk is simply leftover from kittenhood. Kittens need to be born with a desire to drink mother’s milk if they are going to survive, and it’s possible that not all adult cats completely lose that built-in drive.
The same review suggested that cats may just have been conditioned to like milk, whether by us feeding it to them in saucers, or during kittenhood. At least one study showed that cats got relaxed and a little sleepy when they were drinking milk. Ahhhhh….milk.
Is milk safe for cats?
All baby mammals drink milk. Drinking mother’s milk is a criterion for actually being a mammal. But adult mammals do not, as a rule, drink milk. Ever. In other words, humans and cats who go around drinking milk are just weird.
But there’s a reason why adult mammals don’t drink milk: they can’t. (Mostly.)
Why baby mammals can drink milk
When baby mammals are born, their small intestines have a special power.
It’s the job of the certain cells lining the walls of the small intestine to grab nutrients out of food and put them into the bloodstream. In baby mammals, these cells are able to produce lactase, a protein that breaks down milk sugar into smaller, more easily digested sugar molecules.
As mammals are weaned by their mothers, which means they are encouraged to drink less and less milk in favor of solid foods, these special cells lose their ability to make lactase.
By the time a human or animal is an adult, their small intestines are making little to no lactase at all.
Why can't adult cats or humans drink milk?
When you don’t have lactase to break down the milk in your gut, what happens?
Nothing, because you can’t absorb the nutrients from the milk.
Well, not exactly nothing, because all that milk sloshing around skips right through the small intestine and into the colon where it mixes with the bacteria living there.
And some of those gut bacteria LOVE milk. As the bacteria eat the milk, it ferments, giving off a gas that can cause severe pain and bloating, and copious diarrhea.
What about adult humans who CAN drink milk?
I just finished saying that adult humans and animals lose their ability to digest milk. But some people do seem to be able to drink milk. Why?
Some people have inherited special genes that allow them to drink milk as adults
Interestingly, some humans have special versions of certain genes that allow them to drink milk as adults.
These people may be descended from people who needed to be able to drink milk to survive due to a lack of water (or clean water) or food. The survival of these milk-drinking people meant that their genes lived on, and some modern-day humans retain this ability to drink milk as adults.
Most of us are able to produce small amounts of lactase in adulthood
In fact, most (but not all) people who are “lactose intolerant” actually do continue to make a small amount of lactase throughout their lives.
Many people (and some cats) who can’t drink milk can still eat dairy products, like cheese or yogurt, because they have been fermented, which reduces the amount of lactose in them. High-fat dairy products, such as ice cream, also have less lactose to start with.
But my cat can drink milk!
The minute you tell someone that cats can’t digest milk they regale you with a story about this one cat that they had who could drink gallons of milk. This cat had a bowlful of milk every morning!
There are a couple of possibilities that might explain an individual cat’s ability to consume milk.
Some cats might still make enough lactase
Some cats, like some humans, may retain their ability to manufacture enough lactase to digest a certain amount of milk their whole lives. There’s no science to support this hypothesis, but it’s possible.
There may be different enzymes at play
It’s possible that cats manufacture a different enzyme that also has the ability to digest a certain amount of lactose in adulthood. Read this study in a 1968 issue of Comparative Biochemistry and Physiology if this possibility excites you.
Raw milk might be more digestible
There is a controversial theory that raw milk, from cows that eat grass (as opposed to grain), contains lactic-acid bacteria, which produce lactase and thus could, theoretically, break down the lactose in the milk. Lactic-acid bacteria has the ability to survive stomach acid, and would – again, theoretically – continue to break down the lactose from raw milk in a person’s (and presumably a cat’s) gut, before it becomes a problem.
Some people, who believe themselves to be lactose-intolerant, claim that they can comfortably drink grass-fed raw milk but not store-bought pasteurized milk.
At the moment, it’s still just a theory. A miniscule study intended to test the theory, which concluded that it was untrue, was seriously flawed.
Barn cats probably drank milk in the pre-pasteurization days
Until the early-mid 1900s, milk was always served raw. But a tuberculosis outbreak around the turn of the century, that could be traced, in part, to contaminated milk, marked the beginning of pasteurization. Pasteurization is the process of applying heat to food to kill germs.
This theory about raw milk, if it proves true, might explain why we have so many images in our culture – in artwork, in literature, in cartoons, and movies – of cats drinking milk, especially in barns. Maybe, in the pre-pasteurization days, cats did safely drink milk.
But don’t feed your cat raw milk ever
Even if it’s true, even if cats could comfortably drink raw milk as opposed to pasteurized milk, DON’T DO IT. Don’t feed your cats raw milk, which is known to contain potentially dangerous pathogens that could sicken or even kill your cat.
Cat guardians might not know milk is making their cats sick
And the final theory is that cats who drink milk have guardians who don’t notice that it’s making them sick.
Cats, we now know, are attracted to milk.
They may drink it because they can’t help themselves, and because they are unable to put two-and-two together, hours later, when they have terrible stomach cramps and diarrhea.
If you have a houseful of cats, or if your cats go outside, you might not notice that the cat who just drank milk was unwell or had a bad bout of diarrhea.
And you might say, “But my cat loves milk! I give her a saucerful every day!”
Why you shouldn’t give milk to your cats
There are three reasons why you shouldn’t give milk to your cats:
Milk makes cats feel sick
Your cat may love milk. Your cat may beg for milk. But you are still the boss, even if it doesn’t always feel like it.
It’s your job as your cat’s guardian to do the right thing, even if the right thing is hard to do.
Your cat is unaware of the relationship between the milk she drank and the terrible bellyache she has, but now you aren’t. It’s your job to protect her from things that can hurt her.
Milk keeps cats from getting the nutrition they need
Cats, being obligate carnivores, have very, very specific dietary requirements.
We humans are omnivores, meaning we can eat everything. “Omni” means all. That means we can get the nutrition we need from a wide range of food types. Cats cannot.
When cats drink milk, they are filling up on something that lacks the nutrition they need to thrive.
Drinking milk can make kidney problems even worse
There are two ways that drinking milk can put a cat’s kidneys at risk:
- Milk (and even cheese) are high in phosphate, which could further damage the kidneys in cats with Chronic Kidney Disease (CKD).
- The sugars in milk (lactose) draw water from a cat’s body into the intestines, producing diarrhea. Cats are already notoriously prone to dehydration, which is very stressful to their kidneys. Read about why cats are so fussy about drinking water in this post. They don't need milk to cause additional dehydration.
What should I do if my cat accidentally drinks milk?
Research shows that cats can probably drink a few tablespoons of milk without ill effects.
But, for the reasons above, don’t make it a habit.
Can my cat drink lactose-free milk, or Lactaid?
Lactose-free milk is made by adding lactase to regular milk. Adding lactase breaks down the lactose in the milk before it ever reaches your or your cat’s belly.
Most, but not all, people (and cats) who are lactose-intolerant can safely enjoy lactose-free milk. However, a milk manufacturer is allowed to call its product “lactose-free” even if a tiny bit of lactose remains in the product. For some very sensitive people and cats, this makes lactose-free milk an inappropriate choice.
For cats, milk still lacks the nutrition that they need. You shouldn’t give your cat lactose-free milk, except as an infrequent treat.
Cats should not get more than 10% of their daily calories from treats. That means that a cat who is at a healthy weight at about 8 ¾ pounds would be able to afford only 20 calories a day in snacks. 20 calories of milk is a very tiny amount.
Read this post about how much to feed your cat to learn more.
What about special milk, made for cats?
*This post contains affiliate links and I may be compensated if you make a purchase after clicking on my links.
These products are both lactose-free real cow’s milk that has been enriched with extra vitamins and minerals, and with taurine, an essential amino acid. A cat’s body cannot produce enough of its own taurine, and insufficient taurine can cause vision and heart problems, among other things.
The other nice thing about the special cat milks is that they come in tiny portions, reminding you that milk is a treat, not a meal.
Can cats drink sheep or goat’s milk?
Compared to other types of milk, sheeps’ milk contains the highest level of lactose.
Goats’ milk has 20-30% less lactose than cows’ milk and could, theoretically, be easier to digest.
But for the reasons described above, sheep and goats’ milk are not healthful foods to feed your cat.
Is plant-based milk, such as soy, almond, oat, or coconut milk safe for cats?
If your cat has taken a little lick of your plant-based milk from your glass, don’t panic. None of these milks are toxic to cats.
But there are many reasons why you shouldn’t actively feed your cat plant-based milks.
Many of these milks are sweetened, and cats shouldn’t be given sugar, even in tiny amounts. Sugar can lead to weight gain, tooth decay, diabetes, and gastrointestinal problems.
Many of these milks contain oils and thickeners, which are hard for cats to digest and can cause diarrhea.
Some milks contain other additives and preservatives that can also be hard on a cat’s sensitive digestive system.
The most expensive plant milks may contain none of these additives, but they usually do contain sea salt for added flavor. Salt can cause dehydration in cats, which can lead to serious consequences for their kidneys.
What should I do if my cat drinks chocolate milk?
If your cat drinks chocolate milk, you need to contact poison control immediately:
ASPCA Animal Poison Control Center: (888) 426-4435
Pet Poison Helpline: (855) 764-7661
It’s not the milk you have to worry about, but the chocolate. Chocolate can be lethal to cats. Please read more about why it’s so poisonous in this post about foods that are toxic to cats.
Can I give my kitten cows’ milk?
Cows’ milk not only lacks the proper nutrition that a growing kitten needs at a time in his life when every calorie counts, but cows’ milk can cause life-threatening diarrhea in a kitten.
Kittens should drink only their mothers’ milk or a kitten milk replacer, such as KMR, until they are at least four or five weeks old.
Read more about feeding young kittens in this post.
When do kittens stop drinking milk?
Weaning, which is the gradual process of moving away from mother’s milk toward solid food, usually starts when a kitten is three to four weeks old. But it happens slowly, over several weeks’ time.
The timeline can vary, but most kittens are weaned by the time they are five to seven weeks old.
When kittens are weaned, they lose the ability to digest lactose, the main sugar in milk, just like adult cats.
By six months, most kittens have adult levels of lactase.
What do cats like to drink beside water?
I get the struggle to get cats to drink enough water, which is why I wrote this post, Why won’t my cat drink out of her bowl?
If your cat isn’t drinking enough water, and she’s on dry food, consider switching to wet. While there are advantages and disadvantages to each cat-food formulation, which I explore in this post, Wet food or dry? What is better for your cat?, wet food sneaks moisture into your cat’s diet.
Water is the only drink a cat really needs. But, if your cat is a real fusspot about water, and you’re looking for an alternative, consider bone broth.
Bone broth is basically a newish term for stock – the meat broth used in cooking, and it’s basically made by boiling bones until all the nutrients and flavor have seeped from the bones into the surrounding water.
You can easily make your own bone broth for your cat. Here’s a video that shows how.
You can also buy bone broth, but think twice before buying a product intended for humans. Many commercial broths and stocks intended for humans contain onions and garlic for flavor. But alliums, which include onions, garlic, leeks, scallions, and chives, can poison cats.
Bone broth for humans might also contain added salt, which is unnecessary for cats and could be dehydrating.
There are bone broth products on the market especially prepared for pets, however, such as this grass-fed beef bone broth by Caru, this grain-free turkey bone broth by Nulo, and this cage-free chicken bone broth by Made by Nacho.
There are also powered versions of bone broth, which take up less space, allow you to mix up only what you need, and potentially have a longer shelf life. Consider dehydrated chicken bone broth by Nature’s Logic, beef bone broth powder by Native Pet, or beef bone broth with extra ingredients for skin & coat by Nature’s Diet.
Love Pinterest? Here's a Pinterest-friendly pin for your boards!
Dawn LaFontaine is a lifelong animal lover who always seems to have a little pet hair in her keyboard. Her blog, Kitty Contemplations, helps cat guardians better understand and care for the special beings they share their lives and homes with. Her cat-products business, Cat in the Box, sells beautiful, well-made, and award-winning products that she designed to meet the biological needs of cats.
 Leonard WR, Snodgrass JJ, Robertson ML. Evolutionary Perspectives on Fat Ingestion and Metabolism in Humans. In: Montmayeur JP, le Coutre J, editors. Fat Detection: Taste, Texture, and Post Ingestive Effects. Boca Raton (FL): CRC Press/Taylor & Francis; 2010. Chapter 1. Available from: https://www.ncbi.nlm.nih.gov/books/NBK53561/
 Beynen, Anton. (2017). Milk for cats. 10.13140/RG.2.2.24040.06406. https://www.researchgate.net/publication/316665845_Milk_for_cats
 Staff, Hastings. “Are Cats Allowed to Drink Milk?” Hastings Veterinary Hospital, 30 Nov. 2021, https://hastingsvet.com/are-cats-allowed-to-drink-milk-the-answer-is-no-heres-why/.
 Dunn, Rob. “Cats Do Not Drink Milk (except When They Do).” Your Wild Life, 22 Nov. 2016, https://yourwildlife.org/2012/05/cats-do-not-drink-milk-except-when-they-do/.
 “Lactose Intolerance: Medlineplus Genetics.” MedlinePlus, U.S. National Library of Medicine, https://medlineplus.gov/genetics/condition/lactose-intolerance/.
 News Center. “Claim That Raw Milk Reduces Lactose Intolerance Doesn't Pass Smell Test, Study Finds.” News Center, 10 Mar. 2014, https://med.stanford.edu/news/all-news/2014/03/claim-that-raw-milk-reduces-lactose-intolerance-doesnt-pass-smell-test-study-finds.html.
 Janina. “The History of Raw Milk and Pasteurization.” Food Policy For Thought, 6 May 2014, http://foodpolicyforthought.com/2014/05/06/the-history-of-raw-milk-and-pasteurization/.
 Center for Food Safety and Applied Nutrition. “Raw Milk Misconceptions and the Danger of Raw Milk Consumption.” U.S. Food and Drug Administration, FDA, https://www.fda.gov/food/buy-store-serve-safe-food/raw-milk-misconceptions-and-danger-raw-milk-consumption.
 “Vet Q&A: Can Cats Drink Milk?” PDSA, https://www.pdsa.org.uk/what-we-do/blog/vet-qa-can-cats-drink-milk.
 Bower, Emma. “Cats and Kittens: Can They Drink Milk?” FirstVet, 20 May 2021, https://firstvet.com/uk/articles/cats-and-kittens-can-they-drink-milk.
 Beynen AC, 2017. Milk for Cats - Researchgate. https://www.researchgate.net/profile/Anton-Beynen/publication/316665845_Milk_for_cats/links/590ade3ba6fdcc4961777d3a/Milk-for-cats.pdf.
 “Things to Know When Producing Lactose-Free Foods.” Food & Feed Analysis, https://food.r-biopharm.com/news/things-to-know-when-producing-lactose-free-foods/.
 Parker, Richard. “What Kind of Milk Can Cats Drink Safely?” Senior Cat Wellness, 10 Feb. 2022, https://www.seniorcatwellness.com/what-kind-of-milk-can-cats-drink-safely/.
 “Can & Should Cats Drink Milk?” Purina, https://www.purina.com/articles/cat/nutrition/can-cats-drink-milk.
 Staff, Hastings.