Seeds and plants of Matthiola fruticulosa (L.) Maire (M. tristis (L.) R. Br.) have been analysed for glucosinolates. The green parts contain 4-methylthio-3-butenylglucosinolate in addition to the corresponding 4-methylsulphinyl derivative; the seeds only the latter. Both glucosinolates are known from other crucifers, e.g. radish. The alleged occurrence in M. fruticulosa of methylglucosinolate, a widely distributed constituent of members of the Capparidaceae, could not be confirmed. In fact, methylglucosinolate seems to be strictly limited to the family Capparidaceae.