Certain plants manufacture cyanogenic glycosides, which in turn discharges hydrocyanic acid (HCN) upon hydrolysis. HCN is poisonous to both plants and animals as it causes cell asphyxiation. It can be detected in tissues by a test, and an antidote is available if the poisoning is noticed in time. Plants from the genus Lathyrus is also toxic to both humans and animals. These points were discussed, including symptoms, the effects on the body and other sources of these toxins.