Bilious vomiting syndrome is not an uncommon cause of vomiting in dogs. Dogs have a relatively rapid stomach emptying time - typically within 4 hours after a meal, the stomach is once again empty. The stomach contains acid, which is very irritating to the stomach lining, especially when there is no food to dilute the acid. When the stomach is empty, the acid irritates the stomach lining, which can also cause the dog to feel nauseated. Some dogs will not eat during this time because they feel nauseated, which allows the stomach to remain empty and irritated. The dog then vomits, bringing up stomach acid and sometimes bile. You may see clear fluid, or fluid that is yellow or yellow/green in color. The way to break the cycle is to get your dog to eat small, frequent meals throughout the day and evening. The overall quantity of food should not increase, but instead of feeding 2 x daily, feed 4-6 x daily, with the last meal right before bedtime. In addition, some patients benefit from the administration of medication to decrease stomach acid production, such as ranitidine (Zantac) and famotidine (pepcid). For her size, you could give 1/4 of a generic pepcid, 10 mg, once daily, in the evening. Further information on Zantac: http://www.veterinarypartner.com/Content.plx?P=A&A=2234&S=1&SourceID=52 Pepcid: http://www.veterinarypartner.com/Content.plx?P=A&A=620&S=1&SourceID=52 Here's a link to more information about bilious vomiting syndrome: http://en.wikipedia.org/wiki/Bilious_vomiting_syndrome Also, you may want to try to feed her as early as possible in the morning.
Although it's probably not related to intestinal parasitism, it would not hurt to have a fecal sample evaluated for common intestinal parasites. In addition, I would not expect her to have foul breath on a regular basis with this syndrome. To be on the safe side, you could ask for your vet to recheck an oral exam for any infected teeth or gums, and to run a blood work panel to rule out diabetes, kidney disease, and other diseases that can cause an odor to the breath, and could also cause vomiting.
Please give her lots of pets from me, and let me know how else I can help. Sincerely, Dr. Devlin