amygdalin

Apricot kernels are still all the rage in homeopathic remedies-- largely marketed for their source of protein, vitamins, and carbohydrates. But alas, their chemical compound hasn't wavered. 

Apricot seeds are all over the internet - marketed as cancer fighters. But the seeds contain a chemical compound that, when ingested in high quantities (and by high we mean several seeds), can cause cyanide poisoning.