The reasons why cats vomit yellow vomit:

1. It may be due to prolonged hunger. If a cat has not eaten for a long time, excessive gastric acid secretion will cause yellow vomitus. It is recommended to feed the cat an appropriate amount of glucose or nutritional paste at regular times and rations every day.

2. It may be due to overfeeding. If the cat is fed too much, especially too much cat grass, it will cause yellow vomiting. At this time, the cat needs to appropriately reduce its intake.

3. It may be caused by the cat being infected with internal parasites. It is recommended to use internal anthelmintics immediately for deworming.

4. It may be caused by cat illness, such as gastrointestinal inflammation, pancreatitis, etc., which can cause cats to vomit yellow vomit. At this time, the owner needs to take the cat to the pet hospital for diagnosis and treatment in time.

5. It may be that the cat is infected with an infectious disease such as feline distemper virus, causing it to vomit yellow vomit. It is recommended to consult a doctor immediately for treatment with antiviral drugs.