Is the sale of leeches permissible?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
The sale of leeches which are utilized for their benefit, such as those used to suck blood for treating blemishes (*kalf*), is permissible. This ruling is based on the principle that where benefit is derived, the item is treated like fish in terms of saleability. This view is the sounder of the two opinions.
Supporting text
The second opinion holds that selling leeches is impermissible because their utility is rare, thus resembling items that offer no benefit.