Sounds like you are doing the right thing but taking Milo to the vet and having the work up done. Does Milo eat too fast?? We had a cat that did that, so we divided the meal into 2 parts, with a 45 minute wait between rounds. That help stop the vomiting. You also could ask the vet if giving Milo a quarter of a 10mg(2.5mg)Famotidine(Pepcid the trade name is mosre costly). about 20 minutes before he eats, that may help!!! Good luck!