What you need to know is that dogs can regurgitate food or bile a lot easier than us humans. It’s an evolutionary adaption due to their scavenging ways. Basically it allows them to eat just about anything and if their body doesn’t react well to whatever they just ate, they can safely bring it back up and leave it, or if they decide its safe, they can eat it again.
Often you will see dogs eat grass and bring it back up, it’s not a big deal to them. Also if dogs scoff their food too quickly, they often need to bring it up again and give it an extra chew before sending it back down the pipe hole.
When your dog simply regurgitates something and you see that your dog seems fine within itself then usually there is no reason for concern.
Vomiting on the other hand can be more serious. Vomiting is where they bring the food up from deep inside their stomach. This will involve large convulsion from the abdominal area. If your dog is vomiting, first thing you want to do is to check what they vomited. If it looks like something other than food, it may be safest to get a vet to check over your dog.(Put whatever they vomited in a plastic bag or container and bring it alone to the vet so you have it on hand in case your vet needs to examine it.) If it’s just food, keep an eye on him or her to see how they feel. If they are still happy and active it could have been just a passing bug or some bad food or something they picked up when you weren’t watching.
I have known dogs to eat some crazy stuff (conveyor belt, bedding, balls, etc.) and if it’s been vomited out it’s a good thing. However there could be more stuck inside. That’s why a trip to the vet is advisable.
If your dog continues to vomit or looks distressed, tired or weak then a Vet consult is needed. Most often it will be a passing thing that your dog will get over in a few days. On the odd occasion it can be more serious and that’s why it’s best to get checked out by your vet as soon as possible.