In young or elderly cats the risk of dehydration is greater and tummy upsets can be very dangerous. Consult a vet as soon as possible. Any pet that has been vomiting for more than 24 hours should see a vet. If vomiting is not severe or frequent, you can try not feeding your cat for 12 hours, although still allow access to water. Do not feed the cat until at least 12 hours after vomiting has stopped. Then offer a teaspoonful of boiled skinned chicken or white fish, such as cod or coley. If this is tolerated, give a little more after two hours. Keep this diet going for a couple of days, then gradually mix with normal food. For pets with diarrhoea, withhold food for 12 hours, then feed as outlined above. Consult your vet if diarrhoea persists for more than two days or if your pet seems dull or weak and does not want to eat.