A cat holding a sign that reads "Lactose Intolerant"

Are Cats Lactose Intolerant | Symptoms & Alternatives

Are Cats Lactose Intolerant?

Did you know that many cats are actually lactose intolerant? It’s true! Although they may eagerly lap up milk when offered, it often leads to stomach discomfort, making this “treat” more trouble than it’s worth.

Most cats are lactose intolerant. While kittens rely on their mother’s milk during the first few weeks of life, an adult cat’s ability to produce lactase, the enzyme needed to break down lactose sugar, significantly decreases as they age. This means that when an adult cat drinks milk or consumes dairy products like cheese, it can cause digestive issues, including Diarrhoea, stomach cramps, and gas. Many cats love milk, but the truth is that it’s not a good option for most.

A cartoon-style illustration of a cat holding its stomach, with a spilled glass of milk next to it and a sign that reads "No Dairy".

What Is Lactose Intolerance?

Lactose intolerance is a condition that causes digestive issues such as gas, diarrhea, and bloating due to the body’s inability to break down lactose sugar, which is found in milk and dairy products. This sugar is digested with the help of an enzyme called lactase, which young mammals, including cats, produce naturally. Dairy products like cheese and cream are high fat and contain lactose, making them difficult for an adult cat to digest.


While kittens can drink their mother’s milk without any issues, an adult cat becomes an intolerant cat as their ability to produce lactase decreases. Although cats may love milk, it’s not a good option to feed your cat once they reach adulthood, as they no longer need milk in their diet. Instead, offering lactose-free alternatives as an occasional treat is safer.

A confused cat standing in front of a refrigerator filled with milk bottles, cheese, and yogurt.

Giving your cat milk may not be safe

When cats appear in cartoons or movies, they’re often shown eagerly lapping up a bowl of milk. But is cat milk really a good option? Surprisingly, most cats are lactose intolerant, meaning milk and other dairy products can lead to digestive problems for your cat.

Symptoms of Lactose intolerance in cats, a list of the main symptoms.

Lactose intolerance symptoms in cats 

If your cat has consumed dairy products, watch for these common signs of lactose intolerance in cats:

Diarrhea: One of the most common signs of lactose intolerance in cats, which can lead to dehydration. It can be difficult to notice if your cat mainly goes to the toilet outside.
Gurgling stomach noises: Loud or unusual sounds from your cat’s stomach may indicate digestive discomfort caused by lactose.
Bloated tummy: A swollen or firm belly can be a sign that your cat is struggling to digest lactose.
Excessive gas (farting): Cats may fart more than usual due to a buildup of gas as undigested lactose ferments in the gut.
Increased outdoor trips: If your cat is going outside more frequently, it could be due to diarrhea or the need to relieve digestive discomfort.
Dirty, smelly bottom: Cats with diarrhea may struggle to keep their rear clean, leading to a noticeable odor.
Excessive cleaning of their bottom: Cats experiencing digestive upset may lick or clean their bottom more often than usual to relieve discomfort.
Lethargy/low energy: Cats with lactose intolerance may feel sluggish or low in energy as their body deals with the effects of consuming dairy.

These symptoms can cause discomfort for your cat, and in more severe cases, it may be necessary to seek veterinary care.

What happens if a cat drinks milk?

When a lactose intolerant cat consumes milk or other dairy products, their digestive system is unable to properly break down the lactose. Instead of being absorbed, the lactose travels to the large intestine, where it ferments. This fermentation process can trigger various uncomfortable symptoms, typically appearing eight to 12 hours after the cat has ingested the dairy.

A realistic image of an adult cat turning away from a glass of milk, with a red

Are all cats lactose intolerant?

Estimates on how many cats are lactose intolerant vary, but it appears that most adult cats fall into this category. Any cat can be affected by lactose intolerance, regardless of breed or genetic background, making it a common issue among felines.

At what age do cats become lactose intolerant?

Cats are naturally equipped to digest lactose as kittens, thanks to the enzyme lactase, which helps them process their mother's milk. However, as cats grow and are weaned off milk, their lactase production significantly decreases. This reduction typically starts around the age of 8 to 12 weeks, making most cats lactose intolerant as they reach adulthood. Since adult cats produce little to no lactase, they struggle to digest dairy products, often leading to digestive issues. It's important for cat owners to understand that cats lactose intolerant from a young age should avoid consuming milk and other dairy to prevent discomfort or health problems.

A happy cat sitting next to a bowl of lactose-free milk, with a cartoon-style label saying

Why are cats associated with milk?

The association between cats and milk dates back centuries, often rooted in imagery of farm cats lapping up milk from buckets or bowls left by farmers. Historically, milk was an accessible treat for cats, especially on dairy farms where it was readily available. This idea became romanticized in stories, cartoons, and media, reinforcing the belief that milk is a natural part of a cat's diet. However, most adult cats are lactose intolerant, meaning their bodies can't properly digest the lactose in milk. While kittens can digest their mother’s milk, offering cow’s milk or other dairy products to cats can cause digestive upset, making it an unsuitable treat despite the long-standing myth.

How to treat lactose intolerance in cats

There is no cure for cats lactose intolerant, so the best approach is to avoid giving your cat dairy products like milk or cheese altogether.


If your cat develops Diarrhoea after consuming dairy, offer small, bland meals frequently to help settle their stomach. Suitable options include boiled Chicken or white fish, ensuring all bones and skin are removed. Alternatively, you can purchase specially formulated cat food designed for sensitive stomachs, consult your vet for recommendations. Avoid feeding your cat any rich or fatty foods, as these can worsen their digestive issues, and make sure they don’t consume any more lactose containing products.

A confused cat standing in front of a refrigerator filled with milk bottles, cheese, and yogurt.

Can I give my cat lactose free milk?

Lactose free milk or specially formulated cat milk is safe for cats lactose intolerant, as it doesn’t contain lactose and won’t cause digestive problems. However, these products are high in calories, which can lead to Obesity if given regularly. Additionally, they lack Essential Nutrients that cats need for overall health. To keep your cat happy and healthy, it’s best to avoid offering any type of milk. Fresh water is all your cat needs to stay properly hydrated.

If cats are lactose intolerant, why do they like milk?  

Considering that most cats are lactose intolerant, why do they still seem to enjoy milk? The answer lies in the fat content. Milk, particularly whole milk, contains fats that cats find flavorful and appealing. This natural attraction to the rich fats in milk can tempt cats to drink it, even though it may lead to digestive discomfort or upset stomachs afterward.

An infographic style image showing the digestive system of a cat, highlighting lactose intolerance, with icons of milk and dairy products crossed out

What are the most common food intolerances in cats?  

Lactose intolerance is the most common dietary issue in cats. In addition to this, some cats may also have intolerances to certain proteins, such as fish or beef. If you’re worried about your cat’s diet or suspect a food intolerance, it’s best to consult your vet for guidance.

FAQ

Why did we used to give cats milk? 

The belief that cats should drink milk likely stems from their early domestication on farms, where fresh milk was easy to find. Cats may have consumed milk simply because it was a convenient food source when other options were scarce. Additionally, since kittens naturally drink milk from their mothers, this reinforced the notion that milk is a normal part of a cat’s diet. However, the milk that kittens drink is not the same as cow’s milk, which contains much more lactose and is harder for adult cats to digest. In reality, most cats are lactose intolerant and can experience digestive issues if given cow’s milk.

What breed of cats are lactose intolerant?

Lactose intolerance in cats is not tied to any specific breed. Whether a cat is a British Shorthair, Maine Coon, Siamese, or a mixed breed, they can all be affected by lactose intolerance. This condition is a natural part of a cat’s development as they grow out of the need to digest their mother’s milk. Once kittens are weaned, their bodies produce less of the enzyme lactase, which is required to break down lactose in dairy products. As a result, most adult cats are lactose intolerant, regardless of their breed or genetic background. Therefore, it’s best to avoid giving milk or dairy products to any cat, no matter the breed.

What percentage of cats are lactose intolerant?

The exact percentage of cats lactose intolerant is difficult to pinpoint, but studies suggest that the majority of adult cats have trouble digesting lactose. Some research estimates that around 70% of cats are lactose intolerant, while others suggest the number could be even higher. Lactose intolerance in cats occurs because, after weaning, their bodies produce less of the enzyme lactase, which is needed to break down lactose in dairy products. As a result, most cats cannot properly digest milk or other dairy, leading to symptoms such as diarrhoea, bloating, and stomach discomfort. Given how common lactose intolerance is among cats, it’s best to avoid feeding them any dairy products.

Is it possible for a cat to not be lactose intolerant?

While most adult cats are lactose intolerant, there are some exceptions. A small number of cats may continue to produce the enzyme lactase, which allows them to digest lactose without any issues. These cats can tolerate small amounts of dairy without experiencing digestive upset. However, this is quite rare, and it’s difficult to determine whether a specific cat can handle dairy without testing their tolerance. Even if a cat shows no immediate signs of discomfort after consuming milk, regular intake can still lead to long-term digestive issues. Therefore, it’s safest to assume that your cat is lactose intolerant and stick to providing fresh water instead of milk.

Kelly Rushton with her cat Eddie Stafford

Kelly Rushton

Meet Kelly Rushton, a dedicated cat enthusiast and proud owner of Feline Fancy Ltd. With a heart as big as her household, Kelly is the loving mum to 10 charming Ragdoll cats. In her world, felines reign supreme, and she brings professionalism and warmth to everything she does. Through her blog, Kelly shares her wealth of knowledge and experiences, offering insights into cat care, behavior, and the joy of living alongside these majestic creatures.


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