In China and Korea, diagnosing illnesses by tasting feces was practiced.

 〘Tasting Feces〙

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[Overview]

 Tasting feces (shōfun) is a method of diagnosis by tasting human feces. It is said to have been practiced in ancient China and in Korea until the Joseon Dynasty. In Confucianism, when performed for one's parents, it was considered a form of filial piety, and anecdotes remain.

[China]

 The story "Tasting Feces and Worrying"

 A record of diagnosis by examining excrement can be found in the anecdote in "Wu Yue Chunqiu: Goujian's Entry into Service," where during the Spring and Autumn period, when King Goujian of Yue was a prisoner under King Fuchai of Wu, Goujian, in order to make Fuchai believe that he was completely subservient, tasted Fuchai's feces while he was ill and said that he would soon recover. 

 Based on this anecdote, "tasting feces" is also used to mean "flattering someone and having no shame." People who are excessively flattering, like some Japanese people, are called "tasting feces people" (people who lick other people's feces) [1]. The taste of the feces was said to be bitter [2].  

 This is similar to the anecdote of "sleeping on brushwood and tasting gall," where one tastes bitter bear bile to remember humiliation (Refer to the Triple Intervention by Russia (1895) and the Russo-Japanese War (1904)).

 Afterward, stories of tasting feces can also be found in anecdotes from the Northern and Southern Dynasties and the Tang Dynasty. The story of "Tasting Feces and Worrying" remains in "Twenty-Four Filial Exemplars" and "Diary Anecdotes." According to this story, during the Southern Qi Dynasty, an official named Yu Qianlou returned home due to his father's illness, and the doctor told him that he wouldn't know the condition unless he tasted the feces. Yu Qianlou said it was easy and tasted it, and because the taste was different, he realized his father's death was imminent and prayed to the Big Dipper to take his place.

[Korea]

 In Tomo Imamura's "Filial Sons and Virtuous Daughters of Korea" in "Collection of Korean Customs," it states:

　6. When a parent is ill, one tastes their feces. The passage states: "If the taste of the stool is sweet and smooth, the illness will not be completely cured. If the taste of the stool is bitter and rough, complete recovery will occur.  According to this tradition, one can test whether an illness will be cured or not. Since bile is present in the stool, it usually has a bitter taste. Sweet-tasting stool is probably nonexistent." [3]