The reasons why cats have diarrhea and vomiting are as follows:

1. It may be that they have eaten undigested food. Cats’ digestive function is weak. If they eat indigestible food, such as hair, bones and other food, it will easily cause the cat to vomit.

2. It may be that you have eaten spoiled food. Microorganisms in spoiled food can irritate the cat's intestines and cause the cat to vomit. It is recommended that cat owners feed their cats fresh and healthy food.

3. It may be due to eating cold food. If you feed your cat food that is too cold, it will cause vomiting and diarrhea. It is recommended not to feed your cat food such as ice cream and popsicles.

4. It may be that the cat has eaten food that is toxic to the cat. Cats must not eat chocolate, grapes and other foods. These foods are poisonous to cats. The first reaction of a poisoned cat is to vomit.

5. It may be that you have eaten food with strong taste. Cats should not eat foods with strong flavors. Human diets that are heavy in oil, salt, and seasonings are very unfavorable to cats and can easily cause cats to vomit.

6. It may be caused by foreign bodies, poisoning, microorganisms, high fever caused by various reasons, parasites, digestive tract damage, gastroenteritis or other medical diseases.

7. It may be caused by viral infection. Check whether you have been vaccinated, whether the vaccination is complete, whether you have had internal deworming, etc.

8. It may be caused by gastroenteritis, caused by scratches by sharp objects, scratches by rough and hard objects, or other factors that damage the gastrointestinal tract. You also need to go to the hospital for treatment.

9. It may be caused by infectious diseases or other organ diseases, such as feline distemper, pancreatitis, renal failure, etc. The cause needs to be identified and actively treated.