The extraction of flavonoids from Houttuynia cordata Thunb by pressurized liquid extraction has been studied in this article. The effects of several important factors such as the concentration of slovent ethanol, solvent rate, temperature and pressure were investigated by orthogonal array design experiment. Both a high flavonoids yield of 3.152% and a high flavoniods content of 23.962% were obtained with solvent ethanol concentration of 50%, solvent rate of 1.8 mL/min, temperature of 70 degrees C and pressure of 8 MPa. The results are favorable to that of traditional methods of hot soaking and ultrasound-assisted extraction. (c) 2007 Elsevier B.V. All rights reserved.