Dogs will likely recover from mild exposure to onions or garlic, but severe poisoning can be fatal, especially without treatment. If you know you dog has eaten an excessive amount of onions or garlic, you should take him to the veterinarian immediately even if there are no immediate signs.
How long after a dog eats onion will they get sick?
While vomiting and diarrhea may occur within one day, it may take several days to a week after your pet eats onions for symptoms of anemia to appear.
How long should I monitor my dog after eating onions?
Unless your pet ate anything close to that amount or more, it is not recommended to do decontamination for him. With a piece of onion that only weighs a few grams I would not be concerned. Just monitor him for the next couple of days for any GI upset, lethargy, panting or pale gums.
More useful articles on a similar topic 👇
How long after eating something does a dog get sick?How long does it take for a dog to show signs of onion poisoning?