Originally Posted by misslesleedavis1
In general, dogs will experience onion toxicity if they eat 0.5 percent of their body weight in onions, according to "Veterinary Technician" magazine. So a 50-pound dog will experience onion toxicity after eating 0.25 pounds or 4 ounces of onion. If you know your dog ate onions, contact your nearest emergency vet to begin treatment as soon as possible. For a two-hour window after your pup eats onions, the vet can induce vomiting to expel onions from his system. Afterward, the pet needs veterinary care and red blood cell monitoring. Treatment may require a blood transfusion to help restore your pet's red blood cells to health.
Are Onions Deadly for Dogs? | Dog Care - The Daily Puppy
He weighs 120 lbs and ate about 2 at most 3 ounces so I think he will be ok. I gave him ipecac syrup just to be safe since he ingested the onion less than an hour ago. Thanks for the information about deadly levels.