The answer to 'bathroom pet stains' is that common causes include pet urine, feces, and vomit. Symptoms can include discoloration, odors, and staining on floors, walls, or fixtures. Solutions depend on the severity and location of the stains.
For minor stains, you may be able to remove them yourself using an enzymatic cleaner or a solution of water and white vinegar. Blot the area, then clean with the solution and allow to fully dry. For tougher stains or those that have set in over time, it's best to call a professional cleaning service. They have specialized equipment and techniques to fully remove the stain and odor.