The 46-year-old has revealed she is a fan of a detox treatment that involves being covering in blood-sucking leeches, reports The Daily Mail.
The star, who is married to actor Ashton Kutcher, 30, recently visited Austria to receive the "leech therapy".
While on a visit to New York to promote her new movie Flawless, the star told U.S. talk show host David Letterman: "I feel like I've always been someone looking for the cutting edge of things that optimize your health and healing.
"I was in Austria doing a cleanse and part of the treatment was leech therapy.
"These aren't just swamp leeches though - we are talking about highly trained medical leeches. These are not some low level scavengers - we're talking high level blood suckers."
Leech therapy has a long history - ancient Egyptian doctors once considered them a cure-all.
She continued: "They have a little enzyme that when they are biting down in you it gets released in your blood and generally you bleed for quite a bit - and your health is optimized.
"It detoxifies your blood - I'm feeling very detoxified right now. I did it in some woman's house laying on her bed. We did a little sampler first, which is in the belly button.
"It crawls in and you feel it bite down on you and you want to go, 'You bastard.' Then you relax and work on your Lemaze breathing just to kind of relax.
"You watch it swell up on your blood, watching it get fatter and fatter - then when its super drunk on your blood it just kind of rolls over like it is stumbling out of the bar."
Demi said had to prepare for the leeches by shaving and taking a bath in turpentine.
She is convinced the therapy is effective and plans to return to Austria for more sessions.
She said: "You first feel worse then you feel better. But I'm going back - I only got 4 leeches and I feel a bit cheated."
Quipped Letterman: "Are you sure this isn't just menopause?"
source
Video
clip of Demi describing her experience