Eminem brushes his teeth with pest spray.
The 'We Made You' rapper is a huge fan of Dr. Bronner's Magic Soap, which can kill bugs and has 17 other uses, and no longer relies on other toiletries.
A source said: "Eminem is obsessed with the soap. He can't believe he is able to clean his teeth and his body with the same product while he is showering."
The product, which is the USA's number one selling natural soap brand, can be used as toothpaste as well as body wash, shaving foam and deodorant. It will also clean dentures, pets, floors and laundry.
Make-up artist to the stars Bobbi Brown said: "It's probably the finest soap in the universe. I'm obsessed with it. I cannot get enough of it!"
Other celebrity fans include Drew Barrymore and Sandra Bullock.
The soap comes in seven main varieties - peppermint, lavender, eucalyptus, citrus, almond, rose and the unscented baby mild and tea tree, which can be used to treat minor cuts.
Dr. Bronner's Magic soap was established by Dr. Emanuel Bronner, who spent his life on a personal mission to unite mankind, renouncing hate and war.
His strong views, which he expressed during lectures, landed him in a Chicago mental asylum in 1948. He escaped after eight months and continued to give lectures in California, during which he gave out his soap.
When Bronner realised his message was being ignored, he decided to put his views on tiny print on the bottle, which are still featured on the products today.
The soaps can be purchased from www.drbronner.com and up to 70 per cent of the profits go to charity.