The blood is able to transport oxygen from lungs, but the body tissue can t take it up and suffocation occurs. One symptom of prussic acid poisoning is bright red blood since it is full of trapped oxygen. The amount of dhurrin found in plant tissue varies among species. Of all the plants grown in Arkansas, those belonging to the sorghum category are the ones most likely to contain potentially toxic levels. Grain sorghum contains the most, followed by johnsongrass, sorghum-sudan hybrids, then pure sudangrass.
Pearl millet is apparently free of the toxin.
HCN may be produced by a few other plant species. Wild cherry trees produce toxic levels. Problems with wild cherry poisoning occur most often when animals consume wilted leaves after trees have been damaged by storms or pruning. The amount of dhurrin is higher in young plants than in older ones. The dhurrin content of leaves is higher than that of the stems.