Instructions
Clean the cat's litter box frequently. As soon as you notice feces in the box, remove it.
Prevent the dog from getting into the cat's litter box. Some litter boxes have an entrance door or a lid that keeps dogs out. Other boxes have very high sides that a small dog can't get its head over.
Move the litter box to an area the dog can't access. A baby gate will keep most dogs out, but a cat can easily jump over the gate. Consider keeping the litter box in a room behind a closed door that has a pet door sized for cats.
Switch the cat to an automatic litter box. These boxes are more expensive and can be tricky to set up, but they either flush the poop or dump it into a sealed container the dog can't access.
How to Prevent Dogs From Eating Cat Litter & Feces
No one is sure why some dogs like to raid cat litter boxes and eat cat feces, but most dog owners find this behavior extremely unappealing. For dogs, it's just normal, but for their owners, it's a disgusting habit. No one wants to get a wet kiss from a dog who has just eaten a heaping helping of feces, no matter how much you love your pet. But if you have an indoor cat, you must have a litter box, and this means keeping your dog out of it.