My cat ate a spoonful of mayonnaise — how long should I watch her and what signs mean a vet visit?

Monitor your cat closely for about 24 hours after eating mayonnaise. The high fat content commonly causes vomiting or diarrhoea within the first 6-12 hours. Also watch for signs of pancreatitis, which include severe lethargy, repeated vomiting, a hunched back, or refusal to eat. If any of those more serious signs develop, your vet may run blood tests to check organ function. Recovery is usually straightforward with supportive care if only a small amount was eaten, but persistent symptoms need veterinary attention.