dog throwing up white foam &slime

Question
My dog is a pitbull ,4yrs old, about 45lbs., female and no health problems. Although for about a month now every so often she wont eat for the day and will throw up this slimy substance, with white foam in it. It happens about once a week. She will puke 2times in a matter of mins. and then she lays back down. My vet keeps tellin me its just a upset stomach it will pass but i find it odd that for a month or two, once every week is odd! IS this normal? Should i find a new vet? It also seems that the day b4 this happens i have given her a dog treat called Dentastick. IM not sure if thats is the reason or not. After puking she wont eat anything at all. Not even people food which she never turns down. It is a very small amout of vomit but sounds like she is dry heaving alot in between pukes. What should i do. I dont want to take her to the vet if its nothing, but dont want to let it go if she needs medical attention! Please help...Thank u.

Answer
The process of deduction would say that if she vomits after eating a dentastix that you should stop giving them to her. She is not able to digest them apparently and they are causing a gastritis in her stomach.

She shouldn't eat after vomiting for at least 24 hours and she knows this so she is letting her body rest.

Stop giving her these treats and see how she does. Don't give her any treats. If she stops then you will know that's what was causing it. If she still vomits, it could be what you are feeding her.

It's a process of elimination.