Léon Monsel was born on March 13, 1816 in Gironde. He did training courses in chemist's first near of home and then in Paris. He also studied pharmacy in Pharmacy School of Paris where he succeeded on August 12, 1840 and he entered army. He remained in it until his retirement in 1874. He died at Nancy on April 15, 1878. Monsel is overall well known by his publications about coagulation power of ferric sub-sulfate from which he described three preparation ways. Current publications are exclusively foreigner. They point out advantages and disadvantages of Monsel's solution. It is used to day as hemostatic agent in minor surgical procedures such as biopsies in genecology, dermatology, proctology and O.R.L. Besides when he was stationed in Roma he studied Acqua Acetosa (acid salty gaseous water) of this town and later when he was stationed in Bordeaux, he took out a patent about manufacturing varnish from metallic resinates.