If you (or, more likely, your tween- or teenage daughter) have been thinking of henna tattoos as a harmless and less-permanent alternative to regular tattoos, you may have some rethinking to do. People around the country who’ve had what they thought were henna tattoos are reporting redness, blisters, lesions, permanent scarring, and some have ended up in hospital emergency rooms.

The problem is that there’s a big difference between plant-based reddish-brown henna, which is perfectly safe, and “black henna,” which is really a coal-tar based hair dye that contains a nasty chemical called p-phenylenediamine (PPD), which a lot of people are allergic to. Oh, and even though it’s supposedly okay for hair, PPD has been outlawed in many countries for use in any cosmetics that are designed to be applied directly to the skin.

So this Spring and Summer, before you pay for your henna tattoo, make the artist is using the real stuff. Your first hint should be the color. Real henna is not black and the stains it leaves on the skin aren’t either. The same is true for other colors: real henna isn’t blue, yellow, green, or purple. And if you do have a henna tattoo that’s started to itch, burn, blister, or worse, get medical attention right away.

Here are some recommendations/warnings from the Henna Page:

  • PPD paste is jet black.
  • Ask how long it takes to stain and how long it lasts. If the answers are “just an hour or two” and “a week or more”, it’s PPD.
  • Ask what colour it will give. If the answer is “pure black”, it’s PPD.
  • Ask to see an ingredients list. If the artist can’t supply one, or you don’t like what you see, walk away.