Three weeks ago my 5 year old chocolate lab was put on Metacam to help with the pain associated with his hip dysplasia. I was told to watch for any vomiting or diarrhea as side effects. We were trying to find the lowest possible working dose for him. He started a dosage of 35 and he weighs about 80lbs. Eventually we had him down to a dosage of about 15-20. He did get sick one morning about a week and a half into his treatment but it was just once and it's not uncommon for him to vomit once in a while. This past monday he had a night of vomiting - probably vomiting about 6 times through the night - he was eager to eat his food but i opted to take him off the metacam as i was concerned this was the cause. He continued to vomit once a day for the rest of the week. He doesn't seem to have any other problems, when he vomits he does not vomit up his food - he goes outside searching for grass and then will vomit up the grass and clear liquid. After he vomits he is very energetic and playful. Any thoughts on what could be causing this? I have spent a great deal of money on his treatment recently and will take him to the vet asap if it's necessary - but because other than the vomiting, he seems fine, i would like to avoid a hefty vet bill if possible.