Some bioactive compounds in paico (Dysphania ambrosioides) leaves were characterised. By LC-MS/MS-QToF, 20 polyphenols were found: vanillic acid, one p-coumaroyl-hexoside acid derivative, three quercetin-rhamnoside derivatives, one quercetin derivative, two kaempferol acetyl-furanoside-rhamnoside derivatives and twelve kaempferol-rhamnoside derivatives. The content of total phenolic compounds was 645.11 mg/100 g dry weight (DW) of which the highest content corresponded to kaempferol glycosides. Likewise, in the analysis of terpenes, a-terpinene, limonene, p-cymene, thymol, c-terpinene, carvacrol, isoascaridol and a-pinene were found in amounts of 1489.65; 313.1; 104.8; 49.4; 45.1; 22.9; 8.19 and 4.32 mg/100 g DW, respectively. Analysis of lipophilic metabolites reported fatty acids in order of importance: linoleic = linolenic > palmitic > oleic (35.8; 35.4; 26.3 and 2.5%, respectively). a-, b-, cand dtocopherols were found in amounts of 28.78, 7.19, 7.96 and 3.27 lg g À1 , respectively. It is concluded that paico leaves of Peruvian origin present a varied source of bioactive compounds with potential applications for the pharmaceutical and food industry.