In most tourist type places you can find a booth doing “temporary henna tattoos”. An artist paints the tattoo on your skin with a dye called henna.

Henna dye is made from the powdered leaves of the Henna plant. Adding water to the powder makes a paste. Applying the paste to the skin stains the skin and the tattoo will hang around for several weeks (until the outer layer of skin sheds off). Here’s how to make the paste:

There can be two problems with henna tattoos: 1) some people have a reaction to the henna leaves, and 2) some companies add chemicals to the henna leaves. In either case, the henna tattoo can leave a permanent mark. Here is an example:

Five-year-old Boy Left With Intricate Dragon-shaped Scar After Henna Tattoo Goes Wrong – with surprising photo

The problem in many of the cases like this is a chemical additive called Para-phenylenediamine (PPD), as described here. This chemical speeds up the setting time and also makes the henna darker, but many people are sensitive to it. This page contains the following cautions:

Do not use any type of henna product that explains it is “fast acting” or only “takes a few minutes to work”. Also watch out for henna products that are only indicated for the hands and feet. Pure and fresh henna can be applied and give good color outcome anywhere. Before applying henna as Mehndi or hair color, always do a patch test. Remember henna is a plant which can have various levels of inherent chemicals. It is by no means standarized. Doing a patch test first would have saved many from having severe allergic reactions as seen with denatured henna products. Be very careful at street fairs and other public events where you have no time to do a patch test before having a Mehndi design. If you must go ahead, be sure to obtain the proper name and contact information of the artisan in case something adverse happens.

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