In continuation of our research for bioactive compounds in plants, we have found that the methanolic extract of Lysimchia japonica Thumb (Primulaceae) markedly inhibited the Na+- K+-ATPase activity. The whole plants of the species have been used medicinally as an antitussive (1). Previously, salicylic acid and some common flavonoids have been isolated (2). The present note deals with the isolation and characterization of the Na+-K+-ATPase inhibitors, 6-tridecylresorcylic acid and grevillol, from Lysimchia japonica.