Is the sale of venomous substances derived from herbs and plants permissible?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If a substance derived from herbs and plants has no beneficial use, or if a small amount of it causes death, its sale is not permitted due to the absence of permissible benefit. However, if it possesses a benefit and its minor use allows for medical treatment, such as Scammonium (Saqamūniyā), its sale is permissible because it is pure and beneficial, resembling other foodstuffs.