Horses, like any other animal, can suffer from different diseases, pathogens and infections of the digestive and urinary tract. Often these conditions are signs and symptoms of much more serious conditions, many which can be fatal. Some causes of diarrhea or colored urine in horses can also be infections that are relatively localized and easily treated as long as they do not become progressively worse through lack of treatment.

Diarrhea can be ongoing or chronic, or it can be episodic, lasting only a few days. Often diarrhea in horses is due to a highly infectious disease known as Salmonellosis. This condition is caused by the bacteria Salmonella, which is commonly found in small numbers as a helpful digestive bacteria in most horses. For some reason, often illness, colitis or even other health issues or exposure to other infected horse's fecal material, the bacteria multiplies and becomes problematic. The first signs of Salmonellosis usually include a fever and colicky behavior such as kicking at the stomach, lack of energy or appetite and constant lying down and standing up. As the bacterial infection gets worse the horse will start to have severe diarrhea, often with no control of the bowels. There may be excessive gas as well as blood in the diarrhea in advanced cases of the disease.

Horses will rapidly become dehydrated and will quickly start to show signs of weakness and toxicity as the body cannot metabolize and filter the by-products of the infection. In foals the condition can be fatal as the body has no reserves to draw on while the treatment is started. In foals the bacteria may quickly spread from the intestines to the lungs, heart, respiratory system and joints, resulting in complete body failure.

Diarrhea can also be caused by parasite infections in the intestines, poisoning and toxicity, rapid changes in feed as well as other types of bacterial infections. Treatment for diarrhea needs to be based on the cause of the problem and while antibiotics may be helpful they also may worsen the condition, depending on the exact cause. A vet can complete tests of the blood as well as fecal material to determine the cause of the diarrhea and start a treatment plan.

Colored urine, usually noted as a dark red, orange or brownish color, is directly related to the presence of blood or destroyed red blood cells. This is a serious condition in horses and may be caused by diseases such as azoturia, urine tract infections, dehydration or electrolyte imbalance. It is important to collect a urine sample and have it analyzed by a vet to determine the cause of the coloration.

In severe cases a horse with colored urine may have kidney failure or significant decrease in kidney function, poisoning from plants, ergots or other chemicals or compounds in the feed, or even conditions such as hepatitis and jaundice. To help the vet be sure to record how much the horse is drinking, roughly how often they are urinating as well as any other changes in eating, behavior or movement.