Pet stores make a product in the form of a treat. They smell awful and I'm not sure how dogs eat them, but mine did. It neutralizes the acid in their urine. A box is about $10 and last around a month. It does work, but takes at least a couple of days to start. You can also buy a spray, but I think this just colors the grass. Otherwise take some time and train them to go in a designated area. If they are males, there is a product called a "pee-post" It is pharomone sented and helps train them to go around this area. My female boxer didn't really use it. But males are more territorial so you might have some luck.