Stocks of illegal white henna have been seized from beauty salons in Abu Dhabi and destroyed.
The banned substance was confiscated and the offending salons fined up to Dh100,000 during inspection raids by Abu Dhabi Municipality.
The public health department at the municipality did not reveal how much of the plant paste had been seized, nor the number of salons found to be in breach of the law that bans the use of chemically dyed henna.
The municipality said salons repeatedly found to be using the illegal henna risk being closed down entirely.
Henna is a paste made from a plant native to North Africa and western and southern Asia. It is generally used to decorate hands and feet as temporary body art, during special occasions, but can also be used to dye hair.
White henna, which does not contain the natural plant, emerged in the UAE in 2015 and was quickly banned for containing harmful components that can cause skin allergies and infections.
Black henna is also banned in the UAE for similar reasons. While black henna contains a base of the natural plant, petroleum is typically added to the mixture to produce a darker colour that stains the skin for longer.
Black henna has been known to cause severe allergic reactions that leave customers with serious burns and even permanent scarring.
The municipality said natural henna, which has a reddish brown or orange hue, is allowed in the UAE because it is safe to use.
"The materials used for the manufacture of white henna vary, as they are made of unapproved and unknown materials that breach manufacturing standards," the municipality said in a statement carried by Arabic-language newspaper Al Roeya.
The municipality called on the public to avoid using any unnatural henna products and to report any suspected cases of salons using banned products by calling the toll-free number 800 555.
Last month, Dubai Health Authority reminded residents and Emiratis about the harmful effects of black henna as members of the public prepared to try their hand at the popular Eid tradition.
