Wyatt Earp speaking of Doc Holliday. Doc Holliday's father, Henry B. Holliday was a trained pharmacist who served in several wars, including the Cherokee Indian War, the Mexican War, and as a Major in the Confederate Army.
Dogs frequently eat grass to ease stomach discomfort. If your dog's stomach is empty, the grass may cause your dog's stomach to produce more digestive enzymes, and this can result in vomiting bile. Unless your grass is treated with fertilizer or pesticides, it's generally safe to allow your dog to continue eating it, as it can help ease her stomach problems.
There can be different explanations to your dog throwing up yellow foam, but this usually happens when your dog's stomach is empty of food. To digest food, the liver produces digestive fluid called bile that is stored in the gall bladder and released into the small intestine to digest food.