Lascivol was identified as the bitter compound in two Tricholoma species, T. aestuans and T. virgatum, and was previously isolated from the European mushroom T. lascivum. The structure of lascivol was previously solved by X-ray crystallographical analysis but its stereochemistry at C3 remained ambiguous. We thus re-examined the absolute configuration of C3 bearing a hydroxy group using the modified Mosher's method.