The Root of the Behavior
Onions are dangerous in any form, whether they are raw, cooked, hydrolyzed, or in a powder. Symptoms of onion poisoning can vary depending on the size of the dog, the amount he has eaten, and the amount of time it takes him to ingest the onion. Toxicity can show up when a dog has eaten as little as .5 percent of his body weight in onions, which equates to one medium onion for a dog that weighs forty-five pounds. Signs of anemia and onion poisoning can include lethargy, weakness, bluish or pale gums, decreased stamina, and red urine. Hypersalivation (excessive drooling), lack of coordination, and vomiting with diarrhea can also be signs of onion poisoning. These symptoms can come on slowly if your dog has only been eating small amounts of onion over an extended period of time, or suddenly after he ingests a larger portion. It is important to note that if you know your dog has ingested a large amount of onions you need to seek medical attention immediately. Signs of poisoning can take up to three days to present and the longer he goes without treatment the longer, more unpleasant, and more expensive the treatment will be.
Encouraging the Behavior
If you suspect your dog is suffering from onion poisoning or has recently ingested onions, it is important to call your vet immediately. If you feel ingesting small amounts over time has slowly poisoned him, he may need to spend some time in the hospital and could potentially need a blood transfusion or supplementation with activated charcoal. A recent ingestion of an amount the size of a medium onion is also cause for concern. Your vet may have you induce vomiting if the ingestion was less than thirty minutes prior. Longer than that, you will most likely need to bring him in for medical treatment.