Most adult cats are lactose intolerant. Cow's milk often causes diarrhoea and stomach upset. It is not a suitable drink — fresh water is what cats need.

Can kittens drink cow's milk?

No. Kittens need specialist kitten milk replacer if the mother is unavailable. Cow's milk lacks correct nutrition and causes gut upset in kittens.

Is lactose-free milk safe for cats?

Lactose-free cow's milk is less likely to cause diarrhoea but is still unnecessary — high in calories with no nutritional benefit over water. Occasional small amounts are unlikely to harm.

What should cats drink?

Fresh clean water daily. Wet food provides much of daily fluid needs. Some cats prefer running water from a fountain.

Cat Health

Can Cats Eat Milk UK?

Quick answer

**Most adult cats should not drink cow's milk.** They lose the ability to digest lactose after weaning — milk commonly causes **diarrhoea and stomach upset**. Fresh water is all cats need. Kittens without a mother need **specialist kitten milk replacer**, not cow's milk.

Key takeaways

Most adult cats are lactose intolerant. Cow's milk often causes diarrhoea and stomach upset. It is not a suitable drink — fresh water is what cats need.
No. Kittens need specialist kitten milk replacer if the mother is unavailable. Cow's milk lacks correct nutrition and causes gut upset in kittens.
Lactose-free cow's milk is less likely to cause diarrhoea but is still unnecessary — high in calories with no nutritional benefit over water. Occasional small amounts are unlikely to harm.

The full picture

Causes, home monitoring, treatment options and the exact signs that mean call your vet — in the complete guide.

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Frequently Asked Questions

Can cats drink milk?: Most adult cats are lactose intolerant. Cow's milk often causes diarrhoea and stomach upset. It is not a suitable drink — fresh water is what cats need.
Can kittens drink cow's milk?: No. Kittens need specialist kitten milk replacer if the mother is unavailable. Cow's milk lacks correct nutrition and causes gut upset in kittens.
Is lactose-free milk safe for cats?: Lactose-free cow's milk is less likely to cause diarrhoea but is still unnecessary — high in calories with no nutritional benefit over water. Occasional small amounts are unlikely to harm.
What should cats drink?: Fresh clean water daily. Wet food provides much of daily fluid needs. Some cats prefer running water from a fountain.

Reviewed 2026-07-19 against UK veterinary guidance · Information only — not a substitute for seeing your vet.