Q: My cat seems to be peeing in the litter box more often, and when I happen to notice him in it, he seems to be straining to get anything out. He peed in the bathtub last night, and the urine had a pinkish tinge. What do you think is going on with him?

A: One of the most common and frustrating health problems we veterinarians see in cats is urinary stones. Common signs of urinary stones are frequent urination, straining to urinate, pain during urination, blood in the urine (that pinkish tinge you noticed), dribbling urine, peeing in unusual places - such as in the sink or bathtub - and obsessively licking the genital area.

When waste products in urine become concentrated, they form tiny crystals that can grow into larger stones. Stones occur most often in the bladder, but are also found in the urinary tract, the kidneys, or the ureter - the tube that connects the kidneys and the bladder. Sometimes the crystals enlarge so much that they reduce or completely block the flow of urine through the urinary tract. That's potentially fatal.

Your cat needs to see the veterinarian, stat. Catching this problem early and treating it effectively is the best way to prevent it from becoming worse. Some types of stones can be dissolved with a special diet and an increase in water intake. Stones may require surgical removal if they are blocking the flow of urine.