Dogs seem to vomit very frequently, much more frequently than all other animals.
One of the most likely reasons why this happens so frequently is that it is a good defense mechanism.
This protects them from digesting anything that could be dangerous to them.
Another reason it that the part of the brain that controls vomiting is very well developed in dogs which might be why it happens so frequently in them.
Signs that your dog is about to vomit include abdominal contractions, gagging sounds, an arched back, and lowering of the head.
On the most common causes of vomiting is the dog eating something that is not edible like grass or some other substance that irritates the lining of the stomach.
Another common cause of vomiting in dogs is overeating.
Puppies and even adult dogs really like to eat their food very quickly and this often stimulates the need to vomit.
If you have a group of puppies that are competing for food it might be a good idea to separate some of them so they can eat more slowly, that way they don't feel pressured to gorge.
Dogs may also vomit when they're upset, excited, or scared like during a thunderstorm.
Also this is a common symptom with many infectious diseases as well and even some chronic diseases like kidney and liver failure.
If you notice this happening frequently in your dog you should make a note as to whether it is repeated and if there is any pattern to it.
Then you should consult your veterinarian for possible cures.