Quick summary
Vomiting once or twice in a dog who is otherwise bright, eating, and drinking is usually a mild upset — often dietary indiscretion (something they shouldn't have eaten). Most resolves within 24 hours.
But some patterns of vomiting are emergencies. The most important ones to recognise are:
- Unproductive retching with a swollen abdomen in a large-breed dog — this is GDV (bloat) and is life-threatening. Go to a vet or ER now.
- Repeated vomiting (more than 3-4 times in a few hours) with lethargy, refusal to eat or drink, or pale gums.
- Blood in the vomit (fresh red, or coffee-ground-like).
- Suspected toxin ingestion (chocolate, grapes, xylitol, raisins, onions, lilies, rat poison, human medications).
What to watch for at home
If your dog has vomited once or twice and is otherwise well:
- Withhold food for 6-12 hours (water is fine — offer small amounts).
- Reintroduce with a bland meal: boiled chicken breast and plain white rice, in small amounts.
- Monitor for: continued vomiting, lethargy, refusal to drink, diarrhoea, bloody stool, distended belly.
When to call a vet
- Vomiting more than 2-3 times in 24 hours
- Vomiting combined with diarrhoea (risk of dehydration, especially in puppies and small dogs)
- Inability to keep water down
- Any lethargy, weakness, or unusual behaviour
- Puppy (< 6 months), senior dog, or dog with known conditions (diabetes, kidney disease)
Emergency — go now
- Unproductive retching (dog looks like they're trying to vomit but nothing comes up) in any dog over 20kg
- Swollen or distended abdomen
- Pale or blue gums
- Collapse or extreme weakness
- Known toxin ingestion
- Blood in vomit (more than a small fleck)
Common causes (for context, not diagnosis)
- Dietary indiscretion — ate something they shouldn't (bin-diving, table scraps)
- Gastritis — inflammation of the stomach, often from diet change
- Viral or bacterial gastroenteritis
- Pancreatitis — especially after fatty meals; small breeds and overweight dogs at higher risk
- Foreign body — swallowed a toy, sock, bone fragment
- GDV / bloat — large-breed emergency
- Toxin ingestion
- Systemic illness — kidney disease, liver disease, Addison's, etc.
Your vet will rule these out through exam, possibly bloodwork, and imaging.