Capture in summer and autumn. After catching, wash, suffocate with lime or wine, and then dry or torrefaction. Japanese medicinal leeches are usually threaded through the middle part of the body and hung to dry. In addition to threading them, the brown leeches stretch one end of the body to form a narrow strip. Due to the difference in appearance after processing, among the medicinal materials, the dried product of Japanese medicinal leech is called "leech", the dried product of wide-body golden thread leeches is called "wide leeches", and the dried product of brown leech is called "long leeches" .
⒈Wide leeches: the two seasons of summer and autumn are the peak seasons. Those who grow in lakes are large and those who grow in paddy fields are small. After they are taken out, they are dried in the sun or dried in a pot.
⒉Long leeches: The harvesting method is the same as above, but after pulling it out, it is threaded up with a thread, one end of the body is stretched, and it is hung in the sun to dry.
⒊Leech: The harvesting period is the same as that of leech. After pulling it out, it is threaded up. It is often worn from the middle of the body and dried in the sun.