A new protoberberine alkaloid, named 5,6-dihydro-10-hydroxy-2,3,9-trimethoxy-13-methyldibenzo[a,g]quinolizinium (1) was isolated from the 60% ethanol extract of the tubers of Corydalis yanhusuo W. T. Wang, together with a new natural product, 13-methylpalmatrubine (2). Their structures were established by spectroscopic methods. © 2009 Xin Sheng Yao.