Why do coffee bars and bookstores make you poop?

The Mariko Aoki phenomenon

According to this article, Harvard-trained gastroenterologist Dr. Saurabh Sethi caused a stir on social media when he posted on TikTok about how going to your favorite big-box store, bookstore, or coffee shop could signal your intestines when it’s time to go.

“A lot of my patients have shared with me that they have also experienced the same thing.”

The Daily Mail claims that the unusual event got its name from a woman who, while visiting a bookstore in Japan, would get the sudden urge to go to the bathroom. Even though other people acknowledged having the same experience, it doesn’t seem like anyone was able to identify the exact cause at the time.

According to Dr. Sethi, it might be because of specific odors, like those of books and coffee. He claimed that being around coffee might, in a sense, speed things up, even if you don’t drink it.

Therefore, going to Target—many of which have Starbucks locations right at the door—or Barnes & Noble—which of course has its requisite cafe—may have you searching for the closest restroom.

Another notion suggests that the smells of ink and paper together could function as a natural laxative, although further research is needed to confirm this. Additionally, the way we browse for books—often stooping to reach lower shelves—may speed up a trip to the restroom.

Furthermore, excessive relaxation or anxiety can trigger the unexpected emotion that comes with shopping, according to Dr. Sethi. The doctor described how the occurrence is almost a blessing for some constipation sufferers, knowing of individuals who “visit specific stores daily to make their bowels move.”

“Yes! Barnes & Noble, and also my favorite supermarket,” one commenter exclaimed.

“Library in college always did it to me,” recounted one.

“Happens with me every time I am shopping,” another confessed.

This condition is known as the Mariko Aoki phenomenon. As mentioned before, a Japanese woman first wrote about experiencing this in 1985, describing feeling a strong urge to have a bowel movement upon entering a bookstore, even if she had no previous need to go.

This phenomenon is a relatively common experience, with many people reporting similar reactions in bookstores and libraries.

The exact cause is not fully understood, but it is thought to be related to psychological factors and associations between books/reading and the digestive system. It is not considered a medical condition, but rather an unusual physiological response triggered by a specific environment.

While not harmful, the phenomenon can be inconvenient or embarrassing for those who experience it unexpectedly when browsing books. It is discussed and recognized, particularly in Japanese culture, where Mariko Aoki’s original account helped bring widespread attention to the phenomenon.

However, I think this phenomenon is not strictly related to bookstores; it deals more with a sort of psychological relaxation effect that happens when our mind undergoes relaxing stimuli, a bit like hypnosis, in which it is transported to unrestrained thoughts, and the body relaxes as a result. So it can happen when we are in the supermarket wandering the aisles carefree, in a bookshop, or even looking at an old house that takes our mind to distant but pleasant thoughts. I, therefore, believe that the effect is about being surrounded by exclusively positive stimuli that cause a complete relaxation effect, which consequently also causes a bowel movement.