"Three Corpses and Nine Insects" is the Taoist name for internal parasites in the human body. The shapes of three corpses and nine insects are drawn in the Tang Dynasty's Taishang Sutra on Eliminating Three Corpses and Nine Insects to Preserve Life, some of which are basically consistent with the roundworms and roundworms we observe in modern times.

Stomach worms are like toads, or like tigers. Feeding people food makes them hungry easily. A thing that tastes good of flesh and blood has a cold, sweet aroma. A weak person hides his internal organs and has thin bones. Burnt lips and sores in the mouth, stuffy nose and itchy fur. The limbs are tense and the back is tired. Gradually nausea, profuse phlegm and mucus. Vomiting after drinking alcohol and not drinking food. The Qi is trapped in the heart and chest, rushes towards the two flanks, and suddenly attacks the outer kidneys. The Qi is exhausted and Yuehua dies. It first replenishes the heart, spleen, and essence, and then disappears in the yin and soul. When the insects are dissolved, the elixir stays in the face and becomes red. (The picture above is the image of stomach worms in the Taishang’s Scripture of Eliminating Three Corpses and Nine Insects and Preserving Life)