Pelletier was born the son of a pharmacist in Paris, France. He both studied and taught at the Ecole de Pharmacie until his retirement in 1842. His major work was the investigation of drugs, which he began in 1809. By pioneering the use of mild solvents he successfully isolated numerous important biologically active plant products: working with the French pharmacist Bienaimé Caventou (1795–1877) he discovered caffeine, strychnine, colchicine, quinine, and veratrine. Their greatest triumph, however, came in 1817, when they discovered chlorophyll – the green pigment in plants that traps light energy necessary for photosynthesis.