The reasons why a cat vomits water-like liquid with foam: 1. It may be due to long-term hunger. 2. It may be due to overfeeding. 3. It may be caused by the cat being infected with internal parasites. 4. It may be caused by the cat's illness, such as inflammation of the gastrointestinal tract, pancreatitis, etc., which will cause the cat to vomit liquid like water.

What to do if a cat vomits water-like liquid with foam:

1. It may be due to long-term hunger. If a cat has not eaten for a long time, excessive gastric acid secretion will cause vomiting of yellow water. It is recommended to feed the cat an appropriate amount of glucose or nutritional paste, and feed it regularly and quantitatively 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 foam. 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 the cat's illness, such as inflammation of the gastrointestinal tract, pancreatitis, etc., which will cause the cat to vomit water-like liquid with foam. At this time, the owner needs to take the cat to the pet hospital for diagnosis and treatment in time.