A cat’s digestive system can be sensitive, and changes in appetite, stools or behaviour are often some of the first signs that something is not quite right. Good digestive wellbeing starts with appropriate food, access to fresh water, a consistent routine and paying attention to what is normal for your individual cat.
Occasional digestive upset can happen, but repeated vomiting, diarrhoea, constipation, weight loss or reduced appetite should not simply be treated at home with supplements. Cats can deteriorate quickly when they stop eating or become dehydrated, so persistent symptoms need veterinary advice.
What does healthy digestion look like in a cat?
A healthy cat should generally have a stable appetite, normal energy levels and regular stools that are well formed and easy to pass. Because cats are very good at hiding discomfort, small changes can be important.
Cats Protection’s digestive-health guidance lists changes in appetite, vomiting, constipation, diarrhoea, weight loss and changes in behaviour among the signs that can be associated with digestive problems.
1. Keep diet changes gradual
Suddenly changing food can upset some cats, even when the new food is nutritionally appropriate. If you are changing from one complete cat food to another, a gradual transition is often easier on the digestive system unless your vet has advised an immediate change.
During a transition, monitor appetite, stools and general behaviour. If your cat has a known medical condition or is eating a prescription diet, speak to your vet before changing food.
2. Hydration matters more than many owners realise
Cats evolved to obtain a significant amount of moisture from food, so some cats naturally drink relatively little. Fresh water should always be available, but you can also encourage fluid intake by:
- placing several water bowls around the home;
- keeping water away from litter trays;
- using wide bowls that do not press against the whiskers;
- trying a pet water fountain if your cat prefers moving water;
- including an appropriate wet food as part of the diet where suitable.
Reduced drinking alongside vomiting or diarrhoea increases the risk of dehydration. If your cat appears lethargic, unwell or unable to keep food or water down, contact your vet.
3. Pay attention to the litter tray
The litter tray gives you useful information about digestive health. Look for changes in frequency, consistency, colour and ease of passing stools.
Very hard stools, repeated straining, watery diarrhoea, black stools or visible blood are reasons to seek veterinary guidance. A sudden change in litter-tray habits can also be linked to stress or other health problems rather than digestion alone.
4. Avoid assuming human food is harmless
Cats have different nutritional needs from humans and some human foods can be dangerous. Rich leftovers can also trigger stomach upset. Keep the majority of your cat’s intake to a nutritionally complete diet suitable for their age and health status.
Cats Protection also notes that many adult cats are lactose intolerant, so ordinary cow’s milk is not an ideal treat and may contribute to diarrhoea.
5. Stress and digestion can be connected
Changes in the home, new animals, visitors, conflict with other cats, moving house and disrupted routines can all affect a cat’s behaviour and may also influence appetite and toileting.
Make sure your cat has quiet resting areas, hiding places and easy access to separate resources such as food, water and litter trays. If your cat is hiding more than usual, Cats Protection advises considering stress as well as possible illness.
Our guide to calm and everyday support for dogs and cats covers practical ways to create a more predictable environment.
6. Where do probiotics, prebiotics and digestive supplements fit?
Complementary digestive products may contain probiotics, prebiotics, fibre or other ingredients intended to support normal digestive function. They can be useful in some circumstances, but the right choice depends on the individual cat and the reason you are considering them.
Check that any product is specifically suitable for cats, follow serving directions and speak to your vet if your cat has ongoing digestive symptoms, takes medication or has a diagnosed condition.
You can browse our Digestive Health collection for complementary pet-wellbeing products.
7. Hairballs are not always just a digestive issue
Occasional hairballs are common, particularly in cats that groom heavily or have long coats. Regular grooming can reduce the amount of loose hair swallowed. However, frequent retching, repeated vomiting, constipation or loss of appetite should not automatically be blamed on hairballs.
8. Watch body weight as well as appetite
A cat can appear to be eating normally while gradually losing weight. Weighing your cat periodically can help you notice changes earlier. Unexplained weight loss, especially when combined with increased thirst, vomiting or altered appetite, should be discussed with a vet.
When should you call the vet?
Contact your vet promptly if your cat has persistent vomiting or diarrhoea, has not eaten normally, seems painful or lethargic, repeatedly strains to pass stools, loses weight, has black stools or visible blood, or simply seems significantly different from normal.
Kittens, elderly cats and cats with existing medical conditions may need veterinary attention sooner because they can be more vulnerable to dehydration and illness.
Frequently asked questions
Should I change my cat’s food if they have diarrhoea?
Not automatically. Sudden dietary changes can themselves worsen digestive upset. If diarrhoea persists or your cat is unwell, ask your vet for advice.
Do cats need probiotics?
Most healthy cats do not automatically need a probiotic supplement. A vet may recommend one in particular circumstances, and pet-specific products should be chosen rather than human supplements.
How can I encourage my cat to drink more?
Try multiple fresh-water stations, wide bowls, a fountain and suitable wet food. Cats often have individual preferences, so offering several options can help.
How long is too long for digestive symptoms?
There is no single rule because severity matters. Repeated vomiting, significant diarrhoea, blood, pain, lethargy or reduced appetite should prompt veterinary advice rather than waiting for a set number of days.
This guide provides general pet-wellbeing information and does not replace veterinary diagnosis or treatment.