The bark obtained from Prunus serotina, or wild cherry tree, contains tannic acid, a bitter extractive, amygdalin, and emulsin, and these two latter principles, when brought into contact in watery solution, produce hydrocyanic acid.

The effect of cherry bark, as administered, is due to the tannic and hydrocyanic acids and the bitter extractive. None of these, however, are present in sufficient amount to make a strong impression, and the only physiological action is that of a mild astringent and tonic. The syrup of wild cherry bark is much used as the basis of cough mixtures. Its average dose is gr. xxx.-2 Gm.