Hello! Thank you for the query. As long as the vomits are not black or red (like a blood), any other color is acceptable. Green color comes from the small intestine. As she has not been eating much, nothing else than bile (digested by bacteria to green substance), stomach acid, mucus are in the intestine. Lack of fluid intake can be the reason to be worried. With every vomit she loses some fluids and ions. This can lead to serious kidney failure. The reason of vomiting is probably some viral infection of gastrointestinal tract. Most of such infections go away without medical attention. However as she does not drink enough, I suggest you to take her to ER for some drips. Hope this will help. Regards.