Yes, it's possible. If you notice a color change, we recommend you monitor your cat's PrettyLitter to see if the color change persists. This is because cats are sensitive creatures and they can be affected by normal life events like a change in food, weather or short-term stress. If color change persists after 24 to 48 hours, that's when we'd recommend taking your cat to your local Veterinarian. Please also be aware - when PrettyLitter is at the end of its life cycle, it can become saturated and urine can pool at the bottom of the litter box. This concentration of saturated PrettyLitter can cause a reaction that changes the saturated litter blue. If you notice the litter is turning a slushy consistency along with a blue color, it may just be time to change your litter. If you have not had a full month life cycle out of PrettyLitter it may be because you have a cat that urinates more frequently or two cats that use one litter box more than the other. If you are experiencing saturation issues, please contact us about adding more PrettyLitter to your box.