Wenxian county. Wen county is a county under the jurisdiction of Jiaozuo City, Henan Province, which is located in the northwest of Henan Province and the south of Jiaozuo City. Wen county is the place of origin of "four huaiyao" of Dioscorea opposita, Rehmannia glutinosa, Chrysanthemum and Achyranthes bidentata, and is known as "the hometown of huaiyao". Wen county Tiegun Yam, in particular, ranks first among the "Four Huai Medicines" for its authentic quality, homology of medicine and food, and unique curative effect. It is rich in 18 kinds of amino acids and 10 kinds of trace elements and other minerals, and is known as "the food of the gods". It has successively collected the certificates and certificates of "Geographical Indications Products" from the Ministry of Agriculture and Rural Affairs, the former State Administration for Industry and Commerce and the former General Administration of Quality Supervision, Inspection and Quarantine.