Aspirin. Yes, you can give 1/4th of a baby aspirin to a cat but ONLY once every 72 hours. The cat is missing a liver enzyme that helps break down aspirin. This causes aspirin, and many other drugs, to be slowly broken down and thus the effects of aspirin lasts for 72 hours in the feline patient. So, if you gave aspirin three to four times a day to a cat you would certainly have a dead cat by the second or third day. Cat aspirin dose is 10mg/kg once every 72 hours. Aspirin should be given with food. NEVER give aspirin if the cat is also on a glucocorticoid (prednisone) or a non-steroidal anti-inflammatory drug (NSAIDS).