Keriorrhea is an oily, orange-colored bowel movement that occurs when a person consumes indigestible wax esters. Wax esters form when a fatty acid combines with a fatty alcohol.

The Gempylidae family of fish contain high amounts of wax esters in their bodies. These fish are commonly known as snake mackerels, and they include species such as oilfish and escolar fish. When a person consumes these fish, the wax esters may accumulate in the rectum, causing the leakage of orange, oily stool.

In this article, we look at keriorrhea in more detail, including its symptoms, causes, and treatments.

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The symptoms of keriorrhea usually develop within a few hours of consuming oilfish or escolar fish and may last a few days.

The key symptom of keriorrhea is an oily, orange bowel movement. As oil is less dense than water, this bowel movement will appear in the toilet as an orange oil that sits above the water.

Some people may describe the smell of keriorrhea as that of strong mineral oil.

Sometimes, a person may also pass feces alongside the oil. Other times, they may only pass the oil.

Other possible symptoms that may accompany keriorrhea include:

Keriorrhea occurs when a person consumes wax esters from oilfish or escolar fish.

As both fish belong to the Gempylidae family of fish, some people may refer to the wax esters as gempylotoxins and the condition as gempylid fish poisoning.

The exact quantity of gempylotoxins that causes keriorrhea is unknown and may vary depending on a person’s sensitivity.

Research suggests that wax esters make up almost 20% of the body weight of Gempylidae fish. The reason for this is that these fish cannot metabolize the wax esters that naturally occur in their diet. The wax esters accumulate in the fish’s body, including the skin and muscle tissue.

Wax esters consist of a fatty acid and a fatty alcohol. These products are indigestible and nonabsorbable. Therefore, once inside the colon, the gempylotoxins have a laxative effect, resulting in oily diarrhea.

Sellers of these fish sometimes incorrectly label them as other types of fish. In other cases, the fish may appear under a different name, such as gemfish, butterfish, or rudderfish.

In a 2018 scientific letter, healthcare professionals who treated three people with keriorrhea noted that each individual had recently consumed raw fish (sushi) prior to experiencing their symptoms.

Italy and Japan do not allow the sale of escolar fish in their country. The Food and Drug Administration (FDA) advise against the importation and marketing of oilfish and escolar fish.

In most cases, symptoms will disappear after 24–72 hours, but they may sometimes last for up to 90 hours. It is unlikely that a person with keriorrhea will require treatment or hospitalization.

A person experiencing keriorrhea may wish to take the following steps to promote recovery:

  • Resting: A person should consider taking time off work and staying at home. If they need to go out, they should be aware that bowel movements may be unexpected and urgent.
  • Drinking plenty of fluids: There is a risk that people with keriorrhea may become dehydrated. An individual should keep drinking plenty of liquid but avoid alcohol and caffeine.
  • Reintroducing foods slowly: There is a lack of research exploring which foods a person should eat when experiencing keriorrhea. However, based on the standard recommendations of what to eat when dealing with diarrhea, they may wish to avoid heavy meals and consume small portions of bland foods.

Other conditions that may produce oily bowel movements include steatorrhea. This term describes feces that contains a lot of fat.

These types of stools may appear oily, pale, and bulky. They may also have a foul smell.

As with keriorrhea, steatorrhea may cause an oily anal leakage, and a person may be able to see oil on the water’s surface in the toilet bowl.


A person may develop steatorrhea from consuming meals or foods that are high in fat, potassium, or fiber. These may include:

Medical conditions

Some medical conditions can negatively affect the stomach’s absorption of nutrients. Poor absorption of fats may cause steatorrhea. Some examples of conditions that may cause steatorrhea include:

  • Celiac disease: When a person with celiac disease consumes gluten, it triggers an immune response in which the body attacks its own tissues in the digestive tract and stomach. As this response can affect nutrient absorption, it may cause steatorrhea.
  • Chronic pancreatitis: The pancreas is an organ that aids with digestion. Sometimes, it may become inflamed and stop working properly. This dysfunction can lead to poor digestion and issues absorbing fats, triggering steatorrhea.
  • Crohn’s disease: This chronic condition causes inflammation of the intestines. This inflammation can affect absorption mechanisms and lead to steatorrhea.

Learn more about steatorrhea here.

Most people with keriorrhea will recover in a few days, so it is unlikely that they will need to see a doctor.

However, if a person is experiencing regular oily bowel movements, they may have steatorrhea. A person should consider seeing a doctor who can conduct tests to determine the underlying cause.

People with keriorrhea will experience oily orange bowel movements. The condition typically results from consuming the indigestible wax esters present in oilfish and escolar fish.

Although it can be uncomfortable and unpleasant, a person with keriorrhea will likely recover at home without needing medical treatment.