Indigo is a traditional Chinese medicine that has been used for more than a thousand years and has significant curative effects. It has the effects of clearing away heat and detoxifying, cooling blood, calming the nerves, and antibacterial and anti-inflammatory. It has been made into hundreds of different dosage forms of Chinese patent medicines. Xianyou Jian Indigo is a dry powder or agglomerate made from the leaves or stems of the medicinal plant Ma Lan produced in the area of 300-500 meters above sea level in Xianyou County. It is one of the famous and authentic medicinal materials of Fujian's "Four Jianzihao". Its quality ranks first among similar products in the country and has high medicinal value. Xianyou Jian Indigo benefits from a complete and unique set of extraction techniques. The traditional extraction technique has a history of more than 800 years. The equipment used is simple, practical and simple, and it can retain its effective ingredients to the maximum extent. It is a traditional skill with orderly inheritance and extremely high practical value. Indigo, also known as indigo, is the precipitate when making indigo and is also the main active ingredient in indigo. The basic content of Xianyou indigo extraction technology includes the control of the quality of the original plant of Jianqingdai, Indigo, soaking to make "澱", and deep processing. In plant collection, it is often pursued that the peak period of the content of the active ingredients of the medicine (indigo carmine, indigo) is basically consistent with the peak period of production, and the most suitable harvesting period is established based on traditional experience harvesting methods and scientific experiments; in soaking to make "澱" ("澱" is the sediment after soaking Indigo leaves or stems and leaves), Indigo leaves or stems and leaves are placed in a soaking pool for 1 to 2 days in summer and 5 to 8 days in winter. The amount of lime added to the soaking liquid is 8% to 11% of the weight of Indigo stems and leaves; and deep processing is to water-fly "澱" and water in a suitable container at a ratio of 1:1 for 5 to 7 times, and then dry and crush. The original plant of Indigo contains monoindole glycosides such as isatis or indigo. To extract these ingredients from the original plant, the method of adding shell ash or lime is used for processing. This is recorded in ancient and modern books such as "Qimin Yaoshu", "Compendium of Materia Medica", "Sanshanzhi" and even "Putian Development History" and "National Pharmacopoeia Chinese Medicine Practical Handbook". In 1977, Lin Wenxi, a herbal farmer in Shufeng Village, Shufeng Township, successfully conducted an experiment to make "澱" with lime under the advocacy and guidance of his father Lin Qijing, becoming the pioneer of using lime to make "澱". This ended the cumbersome history of using shell ash to make "澱", greatly improved the product quality of Jian Indigo, and made important progressive reforms in the processing of Jian Indigo. It has been passed down for more than eight generations. Xianyou has a history of cultivating Indigo and producing Jian Indigo of more than 800 years, and has gone through three heydays: mainly making and dyeing indigo, mainly using it for medical purposes, and modern standardized production, management and application. Xianyou Jian Indigo traditional processing techniques are a set of relatively complete and unique classic processing techniques formed by generations of medicinal farmers in Xianyou County in more than 800 years of production practice. They can retain the effective ingredients of Jian Indigo to the greatest extent and are the most effective method to extract the ingredients of Jian Indigo so far.