Why Is My Dog Passing The Most Offensive Gas Smell?

I would start With a vet check. It could be as simple as easy to remedy parasites. The suggestions about the teeth and digestion was good too. the food is the last thing to check.

Talk to your vet. It could be a sign of some medical condition.

He may need a type of dog food specifically for older dogs, who sometimes can't digest regular dog food as well. Also have the vet check his teeth, if he is having any trouble with them, like not being able to chew his food up properly that can cause large chucks of food to pass slower through his system and get him bloated and gassy.

The problem is most likely caused by diet. When you say you have changed his food, although it was five months ago, it may have taken this time to upset his tummy. Change his food back, and if the problem gets no better within a few weeks, I would take him to the vets

I feel your pain! My 7 month old lab mix clears the room frequently with his terrible smelling gas! I've had him on probiotics for months but it hasn't helped yet. I heard that it could be parasites, so I plan on taking a stool sample in to the vet. Hope this helps. Good luck!

I have to avoid giving one of my guys beef based foods otherwise he'd knock me out with the stench!

As dogs get older their tummys get more sensitive too. Maybe the change in diet just hasn't suited him? I'm a fan of home making food myself. Especially cause mine are so small. 1/2 a chicken breast or can of oily tuna with boiled rice or cubed carrots & potatoes is more than enough to feed a small breed and doesn't work out too expensive. Them, their tummy and their coats will love you for it