This flavorful plants was once one of the many flavors in natural root beer. The leaves are still used to make sassafras tea in parts of the South and parts of the plant are still used in tea and medicines in some parts of the world. Sassafras contains camphor and safrole, tow compounds which can be poisonous is large enough quantities, though small amounts of sassafras extracts are thought to be purative in folk medicines.
Technically it’s only bitter almond which contains significant amounts of cyanic compounds, but their poison is the reason why raw bitter almonds are no longer legally sold in the U.S. Heating processes the poison and makes them safe to eat.
Only parts of the plant of are poisonous, mainly the leaves. Though some sources claim that small amounts of the poison oxalic acid can be found in the stems as well, it is at levels too low to cause harm to humans.
While roasted cashews aren’t poisonous, parts of the plant contain caustic compounds that will burn human skin, including the fleshy “shell” that surrounds the nut. And this is why you cannot buy cashews in the shell. Fun fact, even the fumes from roasting the nuts can cause burns and severe skin and lung reactions (similar to burning poison ivy and the two plants are related). The poisonous compounds that can be found in or derived from the toxic part of the plant are used for lumber treatments to fungicides to paint to weapons for the military. Yikes!
Surprisingly the “apple” of the tree from which the nut grows is actually edible!