Lotaustralin was isolated as a mixture of two diastereoisomeric forms from the methanol extract of Rhodiola rosea roots, together with the known compounds rosavin, rosarin, rosin, rosiridin, salidroside, and beta-sitosterol. The structure of lotaustralin was established by 1D and 2D-NMR spectroscopy, including 1H-1H COSY, NOESY, HMQC, and HMBC, and FAB and HR MS.