... "of calamine lotion."

Anacardiaceae: a family of flowering plants bearing fruits. Some of those plants produce urushiol, an irritant.

Notable plants in this family include

• cashew
• mango
• poison ivy, oak, sumac
  

That means that poison ivy, poison oak, poison sumac, mangoes, and cashews are closely related.

Most people are aware of the itch (contact dermatitis) so generously given when one touches the leaves or vines of poison ivy, poison oak, and poison sumac. The itch is so remarkable that it has been celebrated in song. My favorite is by The Coasters.

Mango peel contains the irritant urushiol. Presumably, the urushiol is removed before the mangoes get to my local produce stand. I say this because for every festive dinner I make mango salsa, but I never 'break out' in rash. I also eat the peels, but don't get an itchy tongue.

To me, however, the real surprise is that cashew shells exude urushiol. The meat is fine, but touching the shells can make you miserable. In stores you'll see raw & in-the-shell walnuts, almonds, pecans, and such. But you won't see cashews raw & in-the-shell. There are tales, perhaps apochraphyl, about people getting a surprise along with the bag o'nuts they bought from the local Boy Scouts' fund-raiser.

One last thing: cashew isn't a nut; it's a seed. The cashew tree also produces 'cashew apples.'

Read all about it.