My dog is a 3 1/2 year old boxer, she started vomiting a few weeks back, but I didn't think much of it because she sometime thew up when she drank too much water, which I just found out could be megaesophagus, and then she slowly stopped eating. She started vomiting every time she tried to eat, we have brought her to the vet 4 times in the past week, they put fluids under her skin did some blood tests tested her temp, liver and kidneys and all came back fine. They gave her canned perscription dog food to try, which she did not eat. We then took her back and they tested her pancris, temp and circulation which was all fine so proceeded with x-rays which came back good also. We put her on a liquid diet for last weekend feeding her out of a syringe and Monday had her put on an IV all day Monday, over night and Tuesday until 7pm. She ate a 1/2 can of food for them and kept this down, next day she did good but did not want to eat the food so I mixed chicken with the canned food and she ate a little but woke up at midnight and vomited and then coninuted to do so the next morning throwing up water. We tried white rice and boiled chicken but she lost her appitie again and will not eat anything now. Today they are doing a Barvarian Test today (SP?) where they put dye in her and take more x-rays. I'm just looking for any suggestions with what to do next. I love my dog she is the best, but I just feel so helpless...

Ask them to check for lyme disease. It's a long shot, but with the symptoms being so un predictable, it's worth a shot.

I really feel for you and you pup!

Here is an article maybe you coul have a look and see if there is anyhting you and the vet missed,

Why Has My Dog Stopped Eating? Common Problems that Cause Dogs to Lose Their Appetites (http://www.suite101.com/article.cfm/living_with_dogs/117855/2)