Gonzo used to vomit up bile on a regular basis, too. I was very confused by it... I got him checked out for allergies, ulcers, etc, etc.

Now that he is fed a premium, grain-free diet Gonzo no longer gets bouts of upset tummy. Not only that, but his skin, fur, itching, ears, teeth, breath, eyes, poops, EVERYTHING has drastically improved. My guess is that your dog's body is pretty toxic - lots of low quality fillers and dead/dying/diseased meats aren't good for anyone, and he probably has an excess of stomach acids trying to digest all of that stuff. Instead of spending more money on Vet bills and medication, invest that into a species appropriate diet. I used to feed grain-packed foods (Nutro Natural Choice, Biljac, etc) because I believed they were nutritionally complete and I wasn't aware of the many better kibbles available. I didn't know, or even consider, the fact that feeding my dog a diet high in grains/fillers/indegestibles was not good for his digestive system nor for his overall health.

A dog can only digest and gather nutrients from, at the most, 25% of vegetable matter. Foods like Pedigree and Beneful are primarily made up of low quality corn, which is one of the least digestible of all vegetables, as it is. All of that is VERY taxing on a dog's digestive system. An opportunistic carnivore, whose body is built for the consumption of meat, is just bound to react badly to a nearly meat-free diet. Some dogs will live a long life on a diet that is packed with fillers... other dogs are very sensitive to fillers.

I highly, highly, highly recommend checking out Dog Food Project and Dog Food Analysis. Educating yourself on the topic, learning what to look for in a dog food, and finding a dog food that works for your pup will save you a LOT of time, money, and worry. A couple of my favorite grain-free foods are Taste of the Wild, Innova Evo, and Orijen... and they're pretty widely available. If you have a feed store or a pet specialty store (not Petsmart/Petco) near you, check out what they carry and get a bunch of samples. I also recommend giving him a few tablespoons of plain or greek yogurt, to build up good flora, or buying this digestive enhancer. It's great for switching foods and calming an upset tummy. Good luck! Keep us updated.

Also, he sounds a bit bored and understimulated, as far as eating goes. Dogs crave the ripping and chewing that goes along with eating meat. Raw meaty bones are VERY healthy for dogs and VERY stimulating and tiring, as well. Turkey necks/wings, chicken backs, and beef knuckle bones are healthy, fairly easy on the tummy, and will give your dog an outlet for his desire to chew. If you're uncomfortable with raw meaty bones, bully sticks, tendons, and lamb/pig ears are safe and fun for your pup. You might also make him work for his kibble, by putting it in a dog puzzle/treat ball, like a Buster Cube or a Tug-a-Jug.