I have translated the next from a Dutch book on medicinal plants.
Bean (Phaseolus vulgaris) - in general (Fabaceae): Toxicity: residing especially in the seeds and unripe beans is the toxic protein 'phasine'. Raw beans and unripe bodies of fruit, all in general, cause with children repeatedly poisoning effects, because often children recognize the beans as an eatable vegetable. The toxic protein 'phasine' though is destroyed only after a lengthy period of boiling the vegetable, and not by drying. Medicinal value: works as a diuretic, especially where people suffer kidney- and heart disease, rheumatism, in the form of a laxative tea. A nice side effect is that it also lowers the level of sugar in the blood.
Offered by Michel.