A drug that has been described as "eating the flesh" of addicts is believed to have arrived in the US for the first time.
Krokodil is a cheap heroin substitute that gets its name from the effect it can have on an addict's skin, slowly turning it scaly and reptilian in appearance.
The drug is thought to eat away at the flesh of a user to such an extent as to leave the bone completely exposed.
A number of newspapers, including the Independent and Daily Mail, have reproduced photographs showing the damage the drug causes to the human body, while the Huffington Post has published a graphic video.
Krokodil is a mixture of crushed codiene pills and toxic ingredients such as gasoline, cooking oil, paint thinner and lighter fluid.
Its real name is desomorphine, and has become increasingly prevalent in Russia in recent years.
Now the first cases are believed to have occurred in the United States.
'We're extremely frightened'
The Independent reports that officials in the state of Arizona fear an epidemic may be about to break out, after two people in one week attended hospitals showing the same effects of the drug.
Dr Frank LoVecchio, a medical director at Banner Poison Control Centre, has said: "As far as I know, these are the first cases in the United States that are reported. So we're extremely frightened.
"They extract [the drug] and even though they believe that most of the oil and gasoline is gone, there is still remnants of it. You can imagine just injecting a little bit of it into your veins can cause a lot of damage... it eats you from the inside out."
Such a description has been inspired by the way the drug often causes blood vessels to burst, leaving gangrenous wounds to fester on the body.
'A lobotomy patient's vacant gaze'
Krokodil's popularity in Russia has been put down to the cheapness and availability of its ingredients, all of which can be purchased legally.
An investigation centred on the town of Novokuznetsk found that around 20% of the population were addicted to heroin or krokodil.
Time magazine published a profile in 2011 of a krokodil user who said she injected the drug nearly every day for six years, before entering rehab to cure her addiction.
The experience was said to have left her with "a speech impediment, and her pale blue eyes have something of a lobotomy patient's vacant gaze."
The effects of an addiction are quick to detect. The average user has a life expectancy of just two to three years after they start to to take the drug.
There are so far no confirmed cases occurring in the UK, although the Independent reports one doctor as believing he may have encountered one possible incident a few years ago.