For 40 years, Paul Karason of Oregon was fair-skinned, with freckles and reddish-blond hair.
Like most people who grow older, Karason's hair turned white. But that's not all that changed color. His skin is now a bright shade of blue.
Karason said he hadn't even realized it until an old friend came to visit.
"And he looks at me and he says, 'What have you got on your face?' 'I don't have anything on my face!'" Karason said. "He says, 'Well, it looks like you've got camouflage makeup on or something.' And by golly, he came in and he was very fair-skinned, as I used to be. And that's when it hit me.
Karason's blue skin is the result of a rare medical syndrome known as argyria, or silver poisoning. He began using silver as a form of alternative medicine, not realizing what might happen to his skin.
It started a decade ago, when he saw an ad in a new-age magazine promising health and rejuvenation through colloidal silver.
"It was a daisy in a glass of water," he remembered. "The story was that the daisy had been desiccated before it was put back in the water. And [now] it looked like a fresh-picked daisy."
Karason sent away for a kit for making colloidal silver -- a home brew of microscopic silver particles suspended in water. For a while, he was drinking at least 10 ounces a day.
In those first months, he didn't notice a change in his skin color. But there were changes in his health.
"The acid reflux problem I'd been having just went away completely," he said. "I had arthritis in my shoulders so bad I couldn't pull a T-shirt off. And the next thing I knew, it was just gone."
As for whether it was the colloidal silver that had cured him, Karason said, "there's not the slightest doubt in my mind."
But there is plenty of doubt among mainstream doctors. These claims, they say, have no basis in science.
"The FDA has looked at it a long time ago and decided that there is no medical reason for taking colloidal silver," said Dr. Vincent DeLeo, head of dermatology at St. Luke's-Roosevelt and Beth Israel Hospitals in New York.
DeLeo's advice to those who are thinking about trying it anyway? "How about: Don't use it!"
But Karason believed he'd found a miracle cure in colloidal silver and decided it could even help with his dermatitis. Karason said he "started putting the stuff on my face [with] a cotton ball."
First, he said, his face turned blue. But then, the rest of his body changed color as well.
Karason believes that he'd be fine if he hadn't taken that extra step and put the silver directly on his face.
But medical experts like DeLeo believe the damage was already done.
"Paul turned blue because he ingested and applied elemental silver. It got into his blood stream and then was deposited in his skin as brown particles. And when you see those particles through the skin, they appear to be gray or blue/gray."
And doctors suspect that it's not just his skin that's changed color -- his internal organs are most likely also blue.
Paul's reaction when he realized he'd turned all blue? "I kind of hoped it would fade off!"
But it didn't fade off. Argyria is permanent.
And Karason is far from the only one who's used colloidal silver as a medicine. As recently as the 1950s, colloidal silver was a common remedy for colds and allergies.