Two indole glycosides, calanthoside and glucoindican, were isolated from two oriental orchids, Calanthe discolor LINDL. and C. liukiuensis SCHLTR., together with calaphenanthreol, calaliukiuenoside, and bioactive known alkaloids, tryptanthrin, indirubin, and isatin. The structures of calanthoside, glucoindican, calaphenanthreol, and calaliukiuenoside were determined on the basis of physicochemical and chemical evidence. Furthermore, it was found that enzymatic hydrolysis of calanthoside furnished tryptanthrin as the main product, whereas indirubin and isatin were obtained by acid hydrolysis of calanthoside.