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?

Published 19 July 2026Last updated 19 July 20262 min read

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 lactose problem

Kittens produce lactase enzyme to digest their mother's milk. After weaning, most cats lose this ability. Cow's milk contains lactose that adult cats cannot break down efficiently.

The classic image of a cat lapping milk is misleading — many cats develop diarrhoea, wind, and abdominal discomfort after drinking it.

Kittens and milk

Orphaned or rejected kittens need kitten milk replacer (KMR) from a vet or pet shop — formulated with correct protein, fat, and taurine levels.

Never feed cow's milk, goat's milk, or human baby formula to kittens.

What about cheese and yoghurt?

Small amounts of hard cheese or plain yoghurt are sometimes tolerated better — lower lactose than liquid milk. They are still unnecessary treats high in fat and salt. See can cats eat cheese.

What cats should drink

Fresh water — changed daily
Wet food — provides significant daily fluid
Water fountains — some cats prefer running water

Cats with kidney disease especially need good water intake — encourage drinking with wet food and multiple water stations.

Sources & further reading

Facts in this guide are rewritten in plain English from publicly available UK advice. We name the organisation where a specific point comes from their guidance. Links below go to the original pages — use them to read the source material directly.

PETHEALTH+ is independent. These organisations do not sponsor, approve, or partner with this website. Guidance checked against sources listed below (last updated 2026-07-19).

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.