Stephania hernandifolia Walp., family Menisperniaceae, a slender climber ranging over the coastal districts of eastern Australia, is reputed to be a stock poison. It has been examined by Bancroft who isolated a crude alkaloid fraction and by Rennie and Turner who stated that it contained picrotoxin and an alkaloid. In a new investigation, the presence of picrotoxin could not be demonstrated with certainty but a crude mixture of alkaloids which has not yet been separated into its constituents was readily obtained. However, by concentrating and cooling an alcoholic extract of the leaves a pure crystalline substance was isolated in 0.4 per cent yield which was identified as "I-quercitol", previously obtained by Power and Tutin from Gymnema sylvestre Br. The substance, which analysed for C₆H₁₂O₅, contained one molecule of water of crystallization, lost by drying at 118 °C in a vacuum pistol. It did not react with triphenylmethyl chloride but a penta-acetyl and a pentabenzoyl derivative were obtained by the usual methods. After this work had been completed and submitted for publication it was announced by Posternak and Schopfer that "I-quercitol" and viburnitol are identical and that the substance is 2,3,5/4,6-cyclohexane-pentol. The constants of the substance and its two derivatives found in the present work were compared with those reported by Power and Tutin. The agreement between some of the figures was excellent but the wide discrepancies in others at first rendered the identification doubtful. Fortunately, a small amount of Power and Tutin's original specimen of "I-quercitol" was made available for comparison. On re-examination, no depressions were observed on taking mixed melting point of the two substances and of their acetyl derivatives. It must be concluded that the two substances are identical and that the constants given by Power and Tutin are erroneous.