Cats rarely show any indication of illness until it’s progressed to a point that they can no longer hide what’s wrong. PrettyLitter cat litter alerts owners to any possible health concerns with litter that changes color after use, helping to detect feline issues earlier. By utilizing silica gel, the crystals change color after urination. Color changes may indicate a host of potential health issues. Red indicates the possibility of blood, blue indicates high alkaline and bright green shows abnormal acidity. Any color other than a golden yellow or olive green may indicate a need for veterinary care.