1. induce vomiting: after eating crabs, first observe the cat's physical condition, and induce vomiting in time once the cat has symptoms such as vomiting and diarrhea.

2. Feeding ginger soup: The cat only eats a small amount of crabs, and there are no bad symptoms for the time being. You can observe the state of the cat within 36 hours and feed ginger soup to the cat.

3. Get a doctor: If the cat is in a serious condition, you need to take the cat to a doctor for examination as soon as possible, and let the cat receive professional treatment.