Diarrhea
Your judgment regarding the health status of a pet with diarrhea is critical.  Bloody diarrhea with severe straining may require an emergency trip to the veterinarian; diarrhea along with vomiting can be a sign of serious intestinal obstruction that may even need surgery.   A pet with diarrhea and also weakness, pain, vomiting, or agitation may be in real trouble; whereas a pet with diarrhea but few other signs of distress may sometimes be treated at home.  Always inform your veterinarian about the situation and have a fecal sample checked just in case worms or other parasites such as Giardia are a factor.   Withhold food only for 12-24 hours to give the intestines a rest.  Water should still be given frequently but in small amounts.  Call your veterinarian for advice on dosages on KaoPectate or Imodium if necessary.  You may be required to bring your animal in for medical attention if it persists for more than 24-48 hours. Chronic or frequent episodes of loose stool may be a sign of Inflammatory Bowel Disease which often requires veterinary attention.