In the history of Chinese medicine, there have been many famous doctors, but the only one who has been called the “Saint of Medicine” by later generations of doctors is Zhang Zhongjing, a native of Nanyang, Henan Province, whose work “Treatise on Typhoid and Miscellaneous Diseases” is regarded as a standard by the academic circles of Chinese medicine. The influence of Zhang Zhongjing can be seen to be very far-reaching. The doctrine of “tonic earth” is also one of the important components of Zhang Zhongjing’s academic thought. For patients with deficiency labor, Zhang Zhongjing often used a medicine – yam, and achieved good results, there is a legend about yam …… Liu Qi, Department of Internal Medicine, Guangdong Provincial Hospital Zhongjing was walking on the road one day and saw an old man dying on the side of the road. He said to Zhong Jing, “You are kind-hearted and have excellent medical skills, I will definitely help you in the future if you have difficulties.” After the old man left, Zhong Jing continued to save the dead and help the wounded, living countless lives. One year, the people’s disease deficiency labor, the symptoms are pale and white, shortness of breath, abdominal constraint, indigestion, diarrhea, sweating, hand and foot heart bothered by heat, forgetfulness, insomnia, loss of blood, loss of essence, pulse floating large and heavy take powerless, all doctors face this condition, are frowning, there is no good medicine to do, Zhong Jing is also no good method, watching the patient’s condition worsen, even critical life, Zhong Jing is also He was anxious. One day, Zhong Jing was studying medical books at home, suddenly saw an old man waving to him, the old man looked familiar, Zhong Jing followed the old man out …… to two or three miles, the old man stood next to a plant, only to see the plant was long and slender, its stems spread on the ground, attached to rise, leaves such as heart-shaped slightly longer, the axils of the leaves have small green flowers, each decorated like a spike The old man said, “Young man, do you still recognize me?” Zhong Jing suddenly remembered that several years ago he had saved an old man on the roadside and served him day and night, and this old man in front of him was the patient he had cured! The old man said, “Nowadays, there are many patients with internal injuries and deficiency labor, and the treatment of deficiency labor should be based on nourishing the middle earth (spleen and stomach), because the spleen and stomach are the origin of the latter, the source of Qi and blood biochemistry. This plant is called Dioscorea opposita, which can not only satisfy hunger, but also cure deficiency of deficiency of labor, thirst and muscle thinning, and it is sweet in taste and flat in nature, tonic but not stagnant, not hot and not dry. The old man disappeared without a trace without waiting for Zhong Jing to thank him. Knowing that he was a divine being, Zhong Jing did not dare to be negligent and mixed and powdered Dioscorea with other medicines and made a pill called “Dioscorea Pill”, which was given to patients with deficiency labor. Since then, Dioscorea Pill has become a famous remedy for deficiency labor for thousands of years. In fact, the common people usually say that yam is yam, because in the Tang Dynasty, due to avoid the name of Daizong “pre”, yam was renamed as yam, and in the Song Dynasty, in order to avoid the name “Shu”, so yam was renamed as yam, so yam got its name. Today, as one of the representative medicines of the same source of medicine and food, yam is still an indispensable food for everyone’s table.