Abhay Talati, dermatologist, Skin Space, Mumbai says pure henna picked directly from the plant is safe to use. But, today we hardly use natural henna.
"To make it more effective and long-lasting, henna leaves are processed, often chemicals are added. The henna picked directly from the plant will not give the dark colour that the henna cones (with chemicals) give today," Talati told IANS.
The dermatologist says the common problem with henna is allergic reaction.
"Itching of hand and scalp, redness, swelling, burning sensation and in some rare case it can spread to your body or you may face difficulty in breathing," he said.
To prevent reaction, he suggests to test it on a small part of the skin before you use it.
"Whatever brand you have bought, first apply it on a small patch of skin like your arm or at the back of your ear. Leave it for some time, if it causes irritation, do not use it. If everything remains fine, go ahead," said Talati.