Soon after ingesting it cats’ red blood cells lose the ability to carry oxygen. The cats’ gums turn brown, they drool and they become weak and wobbly.
If they survive the first 12-24 hours the liver starts to close down, too. They go off their food, their face, lips and paws swell, their gums and eyes go yellow and their belly swells.
Most cats who ingest paracetamol die unless treated within the first couple of hours.
Aspirin is equally dangerous but more subtle in its effects. Aspirin damages cats’ kidneys and irritates their stomachs.
Very few pain medications are safe for cats. Only give medications prescribed by your vet for your particular puss.