Australian chestnuts

Australian chestnuts are the large seeds of Castanospermum australe, the Moreton Bay chestnut tree native to eastern Australia. Unlike true chestnuts they are not eaten raw, because they contain toxic saponins and other bitter compounds. Aboriginal Australians traditionally processed them into food by roasting, slicing, and prolonged leaching in running water, a detoxification method that made them safe and nutritious. They remain a bush food of cultural rather than commercial importance, illustrating how traditional knowledge can render a toxic seed edible. Modern foragers are warned not to experiment with them casually, since inadequate leaching leaves the toxins intact.