Question: are the shells of cashews poisonous?
Answer: It turns out that the cashew shell is toxic. ... Cashews instead have a lining around the seed that is filled with a nasty fluid. Cashews are in the same family (Anacardiaceae) as mangoes, pistachios, sumac, and poison-ivy. Many plants in this family produce Urushiol, an oil that can cause a nasty, painful rash.