Think twice about getting a black henna tattoo because it may not be temporary after all.

The U.S. Food and Drug Administration warns that people have reported severe reactions, such as blistering, loss of skin pigmentation and permanent scarring, to henna tattoos.

Some reactions, which may occur immediately after or weeks after getting inked, have caused some people to seek medical care.

Traditional henna is made from a flowering plant. It has a reddish-brown color and has been used for centuries to dye skin, fingernails and wool.

In the last decade, henna has been used recreationally, said Tamara Ward, an FDA press officer.

Black henna is different from traditional henna. Though the ingredients, either a mixture of henna and other elements or simply hair dye, are used to create darker and longer-lasting tattoos, the FDA said it’s “potentially harmful.”

“With black henna tattoos, we’ve been made aware that they’re using coal-tar hair dye,” Ward said.

Coal-tar hair dye contains p-phenylenediamine, which can cause severe skin reactions. A tattoo artist may use a PPD-containing hair dye alone.

“By law, PPD is not permitted in cosmetics intended to be applied to the skin,” according to a FDA report. “While states have jurisdiction over professional practices such as tattooing and cosmetology, that oversight differs from state to state. Some states have laws and regulations for temporary tattooing, while others don’t.”

In Florida, black henna tattoos are legal, said Molly Kellogg, a press secretary for the Florida Department of Health.

She said she doesn’t believe there’s legislation about black henna tattoos.

Joe Altizer, manager of Inked Tattoo, 1410 NW 13th St., said the shop offers “the all-natural, brown-red henna,” but it’s not something his staff does often.

“I wouldn’t do henna that’s not naturally derived,” he said. “I think that’s the first mistake people are making.”

Before getting any kind of tattoo, he suggests people research.

“The more education you have, the better decisions you make,” he said.

To his knowledge, there is no accreditation for henna.

Raevon Rolle, an 18-year-old UF public relations freshman, is not a stranger to henna tattoos. She got her first one, which lasted a week, in high school.

Now, Rolle said, she always asks to make sure artists don’t use black henna on her skin.