My cat ate onion or garlic.
Signs come days later.
Cats are the most allium-sensitive species we keep: onion, garlic, chives, and leeks oxidize feline red blood cells into destruction (Heinz-body hemolytic anemia). The cruel part is the delay, the damage surfaces days after the meal.
Published guidance flags every allium, raw, cooked, dried, or powdered, as toxic to cats, with concentrates the worst per gram: onion powder, soup mixes, gravy granules, and garlic supplements pack many bulbs into a spoonful. Garlic is commonly cited as several times more potent than onion. Because red-cell destruction builds over 2-5 days, a cat can seem fine tonight and be dangerously anemic by the weekend; call poison control with what was eaten and roughly how much, and let them set the follow-up bloodwork.
Pet Poison Helpline · 855-764-7661 ASPCA Poison Control · 888-426-4435Signs and the timeline
Sometimes vomiting or drooling on day one, then a quiet gap, then day 2-5: weakness, fast breathing, pale or yellow-tinged gums, dark reddish-brown urine, and collapse in severe cases. The delayed pattern is documented and is exactly why waiting for symptoms fails.
The routes cats actually take
The classic: baby food or broth containing onion powder fed to a sick or picky cat, sometimes for days in a row (small repeated doses stack). Also buttered onion-cooked pans licked clean, dropped garlic bread, gravy, stir-fry scraps, and "immune-boosting" garlic supplements given on purpose. Check labels: onion and garlic powder hide in most savory human food.
What NOT to do
Do not wait for signs; the treatable moment is early. Do not feed broths, gravies, or baby food to cats without reading the label for onion and garlic powder. Do not give garlic to any pet as a flea remedy; it does not work and it is a poison.