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Sweet, cold, slippery, non-toxic.

Invention: Jue (Pteridium aquilinum var. latiusculum) is cold and slippery in nature and must not be eaten raw. *Soushen Ji* records that a soldier broke off some Jue to eat; he felt depressed and ill, later vomiting a small snake which gradually dried up into Jue. Sun Simiao stated that long-term consumption leads to the formation of *jia* (abdominal masses), which indeed aligns with the previous account.

Also known as Tudou (Dioscorea bulbifera)
Sweet, pungent, cold, slightly toxic. It should not be irrigated with water, otherwise it becomes bitter.

Invention: Tudou resolves the toxicity of various medicines. When crushed raw and taken with water, one should vomit noxious substances and then stop. Cooked, it is sweet, delicious, satiating, nourishes the intestines and stomach, and clears heat cough. For children, cooked consumption can make chickenpox/varicella lesions sparse and resolve toxin from chickenpox or sores. Ash from its vines applied topically to ulcerated chickenpox prevents scarring.

Also known as Shanyao (Dioscorea opposita), renamed due to Emperor Daizong of Tang's personal name Yu (蓣) and Emperor Yingzong of Song's personal name Shu (薯).
Sweet, neutral, non-toxic. Consuming it with wheat flour may induce Qi stagnation; it should be used after slight roasting.

The *Shennong Bencao Jing* states it treats damage to the middle jiao, tonifies deficiency and emaciation, eliminates pathogenic cold and heat, supplements the middle and boosts Qi and strength, promotes muscle growth, and strengthens Yin. Long-term consumption brightens the eyes and ears, lightens the body, prevents hunger, and prolongs life.

Invention: Shanyao enters the Taiyin channels of the Hand and Foot. Its white color corresponds to the Lung. Its sweet taste corresponds to the Spleen. It greatly tonifies the Huangting (Middle Jiao/Spleen-Stomach), treating Qi deficiency causing clear empty-heat. Thus, the *Bencao Jing* notes it treats middle-jiao damage and pathogenic cold/heat; it tonifies without stagnation and warms without excessive heat. It also boosts Qi and strength, promotes muscle growth, strengthens Yin and secures the Kidney, stops seminal emission, and reduces frequent urination. The Lung is the upper source of the Kidney; if the source is nourished, how could the flow not benefit? The *Jin Gui Yao Lue* uses it in Ba Wei Wan to strengthen Yin, and it serves as the sovereign herb in Shu Yi Wan. It primarily treats deficiency labor insufficiency, wind-pathogen myriad diseases; its sweet-warm neutral tonification does not hinder the expulsion of chronic accumulated pathogens. Fresh Shanyao mixed with raw crucian carp brain and pounded is applied externally to reduce swelling; pounded and mixed with Chuanxiong powder and rock sugar frost, it is applied to breast lumps (ru pi) and old painful hard swellings that do not suppurate. However, application causes unbearable itching, which subsides after enduring for a long time, healing within a few applications. Its aerial tubers are named Lingyuzi, tonifying deficiency, strengthening waist and legs, and benefiting the Kidney. A variety called Ganshu has a slightly purple color compared to Shanyao, is slightly sweeter, has a slightly greasier texture, and is slightly warmer in nature, offering slightly superior spleen-tonifying and kidney-strengthening effects. People in Guangdong use it as a staple food substitute; now it is widely planted in Huizhou and Ningguo, named "Shu". The pronunciation "Ru" resembles the character shape and phonetic component of "Shu", an error arising from long-term transmission.