Stools

• If your cat passes several loose, bloody or watery stools, he may be suffering from diarrhea.
  
  

Odor

• If your cat has an unpleasant odor that doesn't go away for several hours, he may be suffering from diarrhea.
  
  

Weight Loss

• If your cat is losing weight or seems unusually lethargic, his body may by experiencing a nutrient deficiency due to diarrhea.
  
  

Vomiting, Appetite

• If your cat is vomiting, seems excessively thirsty or has an unusually small appetite, it may be due to the effects of diarrhea.
  
  

Soiled Bottom

• If the fur around your cat's bottom is frequently stained, it could mean that he is suffering from diarrhea and is unable to keep himself clean in his usual manner.
  
  

Fever, Pain or Swelling

• Any sign of fever, abdominal swelling or pain is an an indicator that your cat may be suffering from illness, possibly diarrhea.