My dog sometimes vomits after eating something else or a chew stick, sometimes undigested food, sometimes white foam, but no other problems. What’s going on?

Frequent vomiting in a dog can have many causes, such as chronic gastritis, pancreatitis, liver disease, or parasite infection. These affect digestion and make it sensitive to new food, so vomiting occurs. Take the dog to a vet to confirm and treat.

If it’s a puppy, the gut may simply be immature and weak, causing easy vomiting. Give pet probiotics and avoid foods other than kibble for now.