Hi there, and thanks for your question. I am a licensed veterinarian and would be happy to try to assist you and your dog. With one episode of having vomited, I would not be overly concerned yet. Puppies have sensitive stomachs, and this could be caused by having gotten into something that disagreed with her stomach, or could even be stress related. What I would do is withhold all food and water and do not let her ear ANYTHING, including grass, for the next 6 hours. If she does not vomit, you can give her 1/2 cup of water. If she holds that down for a half hour, you can give her a bland diet of boiled chicken breast mixed with white rice in a 50/50 mixture. You should give her 1/4 cup or less, and then if she holds that down you can feed it to her in 4-5 small meals per day for the next 2 days. If all goes well, then you can switch her back to her usual food. If you do this, and she continues to vomit, then I would see a vet. Hope this helps... best of luck.