Gerard de Solo occupied the position of maitre-regent at the University of Montpellier during the first half of the XIVth century. He wrote four major treatises, including a Commentary of the IXth book of Almansor of Rhazes, renowned for its medicinal compounds. The best witness of his age, the work of Gerard de Solo enables us to draw conclusions on the character of pharmacopoeia of Montpellier in the middle of the XIVth century.