Cassiadinine, a new chromone alkaloid and (+)-6-hydroxymellein, a new dihydroisocoumarin isomer have been isolated together with three triterpenoids, cycloart-23-en-3β,25-diol, friedelin and betulin, a chromone derivative, 5-acetonyl-7-hydroxy-2-methylchromone and γ-sitosterol from the petrol and chloroform extracts of the flowers of Cassia siamea. © 1986.