Originally from tropical Asia, the plant is cultivated in the US, mostly for ornament, and is found as an escape in southern regions. Young leaves, flowers, and tender, immature pods are edible raw or cooked. The ripe seeds are eaten cooked, either boiled or roasted. In Asia, they are made into noodles. The Hyacinth Bean is cultivated as a vegetable throughout the tropics. Many local species are used as food in tropical Asia, Africa, America and Australia.
Mature and dry beans have got a high amount of cyanogenic glycosides in them. Not good for you. Mature or dry beans must not be eaten raw. They have to be cooked. That means boiling soft raw mature beans or roasting as heat drives away the toxin. If they have dried — read they are hard — that means soaking overnight then boiling them a long time in a lot of water. Or, boil unsoaked dry beans in a lot of water twice. Actually, that is what one often has to so with many dried beans. And the older any bean is the longer you have to cook it.