[header] How to diagnose and treat urinary problems in guinea pigs [title] Look for blood in your guinea pig's urine. [step] Examine your guinea pig's bedding and the hair around its bottom for dried blood. Blood typically dries a dark rust color rather than bright red. 
[title] Examine bedding for infrequent urination. [step] When you change your guinea pig's bedding, look for bedding that seems overly dry with no urine spots.