Numerous fruits from the rose family contain cyanogenetic glycosides, which upon ingestion release hydrogen cyanide gas. These include seeds from cherries, apples, plums, almonds, and peaches.

It would take an excessive amount to kill you but the threat is very real. There have been reported deaths in Turkey, a large apricot exporter, for this reason. If you're baking with fruits be sure to take out the seeds.