Cat keeps vomiting white foam

A cat vomiting white mucus or foam is generally caused by eating something bitter or irritating, prolonged hunger, poisoning, stress, hairballs, or vomiting from severe pain. If the cat vomits foam on an empty stomach in the morning, it is usually because it is too hungry; feeding on a fixed schedule avoids long-term hunger.

If vomiting is frequent, withhold food for 4-6 hours, and after symptoms ease, offer some bland food and probiotics to regulate the stomach. If the cat may have eaten something irritating, let it recover and drink more water to aid metabolism. If vomiting comes with lethargy, diarrhea, convulsions, or other symptoms, take it to the vet promptly.