Allium fistulosum L. is a species of small onion that grows profusely in the Loreto region and contains quercetin with a broad spectrum of activity as an antioxidant, anti-inflammatory, anticancer, antiarthritic, etc. The objective of the present work was to isolate quercetin and characterize it by measuring its physicochemical and spectrometric parameters. The samples were collected in the town of Zungarococha, district of San Juan Bautista, province of Maynas, region of Loreto. The dry bulb was pulverized and degreased with petroleum ether in Soxhlet equipment, then macerated for 40 hours in 95º ethanol with intermittent agitation, filtered in a Buchner funnel on filter paper, purified with norite and yellow crystals in the form of needles were obtained. The measurements of its physicochemical characteristics showed the following values: melting point 312ºC, Rf in Silicagel 27 and po...