Abstract: AimTo study the biotransformation of kaempferitrin, a major chemical principle of the fruits of Siraitia grosvenori (Swingle) C. Jeffery, with human intestinal flora. MethodsThe kaempferitrin was incubated with human intestinal flora. The biotransformation products were isolated and purified by chromatographic methods and the structures were determined by spectroscopic techniques. Results Kaempferitrin was converted into kaempferol 3-O-α-L-rhamnoside (afzelin, I), kaempferol 7-O-α-L-rhamnoside (II), kaempferol (III) and p-hydroxybenzoic acid (IV) by human intestinal flora. ConclusionThe structure of kaempferitrin can be biotransformatedly converted by human intestinal flora.