Can Cats Eat Onions?

No. Cats should never eat onions, as they are poisonous to cats. All parts of the onion plant are toxic to cats, including the bulb, leaves, and flowers. Onion consumption can cause a condition called Heinz body anemia in cats, which can lead to damage of the red blood cells. Symptoms of onion toxicity in cats can include vomiting, diarrhea, lethargy, weakness, pale gums, and rapid heart rate. If your cat has eaten any part of an onion, contact your veterinarian immediately.