Black dye can harm internal organs

Side-effects from the use of natural henna staining are rare, but dyes mixed with the substance can cause serious allergic reactions and even lead to kidney and liver failure, a medical Web site warns.

According to an Internet 'About' Guide on Allergies, a natural henna stain should be reddish-brown, not black.

'If the stain is black then phenylenediamine (PPD) dye has probably been added to the henna to give this colour. PPD is a very toxic dye,' the guide warns.

Henna is a small shrub found in North America and the Middle East. The leaves and twigs are ground into a fine powder and mixed with water or lemon juice to make a paste. It is painted on fingernails, hands and other parts of the skin in patterns.

The paste is left on the skin for several hours or overnight before it is scraped off, leaving a red-orange stain.

Henna artist Catherine Cartwright Jones says in the Internet guide that henna staining has been used for more than 9,000 years in more than 40 countries by women to beautify their hands and feet. The rise in popularity of the body art among youth in the West is due, in part, to its use by celebrities such as Madonna, Sting and Demi Moore.