Buttery and succulent, the related oil fish (Ruvettus pretiosus) and escolar (Lepidocybium flavobrunneum)) are considered to be two of the most palatable fish in the world. But before you run out to your local fish market in search of these delicacies, you’d better stock up on toilet paper because you’re going to spend a lot of time in the restroom after your scrumptious meal.

With such a large number of species in danger of being over-fished and others posing health risks due to their high mercury content, the seafood industry needs alternatives that taste great, are cheap, sustainable and healthy to consume. The oilfish and escolar seem perfect choices, and although they’ve been popping up in restaurants and fish markets around the world, there is one dirty little secret that those who sell them sometimes forget to reveal – they cause explosive, oily, orange diarrhea. I know it sounds bad, but there is a way to avoid this embarrassing and highly uncomfortable side effect. The fish are safe to eat if they are consumed in portions smaller than six ounces, but most people are either unaware of the consequences or they just can’t help themselves because they are so damn delicious, so they go for full servings. People who actually went through this kind of ordeal have reported the oily discharges are almost impossible to control and often lead to embarrassing accidents.

Apparently, these two snake mackerels cannot metabolize the wax esters naturally found in their diet. The esters, which are very similar to castor or mineral oil give the flesh its distinctive oily texture but also cause gastrointestinal symptoms. Escolar and oilfish flesh has a wax ester content of around 25%, and in large-enough quantities acts as a natural laxative. The condition it causes is called keriorrhea (Greek for “flow of wax”) and is very similar to diarrhea, only the body expels orange oil instead of liquid bowel movement. Onset may occur between 30 minutes and 36 hours after the meat is consumed. Accompanying symptoms may include stomach cramps, diarrhea, headaches, nausea, vomiting, and anal leakage.

Because of the unpleasant side-effects of eating oilfish and escolar, countries like Japan and Italy have banned the importation and sale of these fish, while Canada, Sweden and Denmark require they be sold with warning labels. In the US, the Food and Drug Administration has warned consumers about the dangers of eating oilfish, but lifted the ban in 1992, because the fish is non-toxic and poses no health risk. It might make a fool of you in front of your friends, but it won’t kill you. However, the great taste of these fish makes them very popular in a number of Asian countries where they are consumed knowing full well the embarrassing and uncomfortable side effects.

Sources: Rocketnews24, The Kitchn, Wikipedia