Cats can eat watermelon before vaccination, but it is not recommended to eat more. Cats do not need to fast before being vaccinated and can eat normally. Watermelon can provide cats with some nutrients and replenish moisture. However, watermelon contains high sugar content, and cats who eat too much watermelon may be at risk of developing diabetes. Cats’ intestines and stomach are relatively weak, so don’t give them iced watermelon.

Cats need to pay attention to their diet after vaccination:

1. Cats can eat some high-protein foods after vaccination. Antibodies are proteins and require a large amount of amino acids to be synthesized. High-protein bookstores can help with the synthesis. However, feeding needs to be in moderation to prevent cats from indigestion.

2. Don’t eat food you haven’t eaten before. If you eat something you haven't eaten before, causing allergies, your immunity will fail.

3. Do not give deworming medicine to cats within 10 days after vaccination. If you take anthelmintics at this time, it may aggravate vaccine reactions, such as vomiting, diarrhea, etc.