It is not always easy to detect illness in your cat. You must look for subtle signs that may indicate a potential problem. Call your veterinarian if you notice:
Constipation or diarrhea lasting for longer than 48 hours
Refusal to eat for more than 24 hours
Vomiting, gagging, sneezing, or coughing repeatedly
Gasping or shortness of breath
Looking or acting sick (red, watery eyes; dull, rough coat; sluggishness; abnormal hiding)
Progressive weight loss over a period of two to four weeks, or a slow but steady weight loss over a longer period
Reddened or swollen gums due to accumulated tartar or loose or infected teeth (usually accompanied by problems with eating)
Drinking or urinating excessively
Straining to urinate