Diarrhea (Long-term) in Cats

Chronic Diarrhea in Cats
 
Feline chronic diarrhea is defined as a change in the frequency, consistency, and volume of feces for three weeks or with recurrence. The cause of diarrhea may originate in either the large or small intestine.
 
Symptoms and Types
 
Symptoms vary depending on the cause and origin. If diarrhea originates in the small intestine, symptoms include:

Unusual volume of feces
Weight loss
Abnormally frequent defecation
Black tar-like feces (melena)
Vomiting 

  ...read more

  • Cat Health Conditions

Source: 

Visit PetMD for more information about this condition.