Samantha throws up regularly.  I check it, and if it just looks like she ate too fast, I don't worry about it.  Dogs do throw up.  If it continues, I call the vet.  99% of the time, it is nothing.
 
Good question, though.  I used to call my friend who had experience with dogs every time it happened.  That was after I quit calling the vet every time it happened in her puppyhood! 
