A systematic phytochemical study of the commercial extract of Luo Han Guo (Siraitia grosvenorii) resulted in the isolation of an additional minor new cucurbitane glycoside, mogroside V Al (1). The structure of the new compound was characterized on the basis of 1D (1H and 13C NMR) and 2D (COSY, HMQC, HMBC and NOESY) NMR and high resolution mass spectral (HRMS) data, as well as hydrolysis studies.