Keriorrhea refers to oily, orange-colored stools that occur when a person consumes indigestible wax esters. Wax esters form when a fatty acid combines with a fatty alcohol.

The Gempylidae family of fish contains 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.

This article explains 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, some people may refer to the wax esters as gempylotoxins and the condition as gempylid fish poisoning.

The exact quantity of gempylotoxins that cause 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 because they 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, the gempylotoxins have a laxative effect once inside the colon, 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) before experiencing their symptoms.

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

In most cases, symptoms will disappear after 48 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 benefit from steps to manage diarrhea symptoms, including:

  • Rest: A person should consider taking time off work and staying home. If they need to go out, they should be aware that bowel movements may be unexpected and urgent.
  • Drink plenty of fluids: There is a risk that people with keriorrhea may become dehydrated. Affected people should keep drinking plenty of liquid but avoid alcohol and caffeine.
  • Reintroduce foods slowly: People may benefit from eating bland foods, such as white rice, bananas, or foods lower in fiber.

Further research is necessary to understand the best treatment plan specific to keriorrhea.

Other conditions that may produce oily bowel movements include steatorrhea. This term describes feces that contain a lot of fat. Steatorrhea may cause a person’s stools to be:

  • bulky
  • oily
  • loose
  • pale
  • foul-smelling

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 high in fat, potassium, or fiber. These may include:

  • nuts
  • oily, high fat fish
  • foods high in trans fats

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.

Most people with keriorrhea will usually recover within 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.

Below are some common questions about keriorrhea.

Is keriorrhea serious?

The severity of keriorrhea symptoms may depend on how much fish a person eats. However, people typically do not experience other abdominal symptoms, and symptoms usually resolve within a couple of days.

Is orange oily stool serious?

Orange, oily stools can occur after a person ingests fish from the Gempylidae family, such as escolar fish and oilfish. Oily, orange stools due to this will typically resolve within a few days, but people should speak with a doctor if oily stools persist.

How does someone fix oily stools?

Treatment for oily stools may depend on the underlying cause. Doctors may recommend avoiding foods that cause oily stools, or they may prescribe medication to treat underlying health conditions that may be causing oily stools.

People with keriorrhea will experience oily, orange bowel movements. The condition typically occurs after eating the indigestible wax esters 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.

People who experience ongoing fatty or oily stools or stool changes with other symptoms, such as severe abdominal pain, should speak with a doctor.