Blackthorn

The flowers, bark, leaves and fruits are aperient, astringent, depurative, diaphoretic, diuretic, febrifuge, laxative and stomachic. An infusion of the flowers is used in the treatment of diarrhoea (especially for children), bladder and kidney disorders, stomach weakness et. Although no specific mention has been seen for this species, all members of the genus contain amygdalin and prunasin, substances which break down in water to form hydrocyanic acid (cyanide or prussic acid). In small amounts this exceedingly poisonous compound stimulates respiration, improves digestion and gives a sense of well-being. Source: https://pfaf.org/