In the US and UK teenagers smoke a powerful hallucinogen, video their experiences and post the results on YouTube. The substance is legal. Its defenders say it is harmless. To its opponents it is a potentially dangerous substance that must be investigated.
"My body felt like it was a palette of paint thrown on a canvas and slowly moving down it."
This description of the effects of digesting the plant salvia divinorum - a relative of common sage - sounds like a parody of 1960s mind-expanding hippies. But it is not untypical of a curious YouTube-centred subculture. Mexican shamans have been using the plant as part of religious rite for thousands of years, but it is now one of a range of "legal highs" sold on both sides of the Atlantic.
Smoked, the effect can be intense but lasts as little as 10 minutes, while chewing it creates a longer period under the influence. Its defenders say it is neither toxic or addictive, but legislators have been concerned enough for it to be banned in Australia, a number of European nations and a handful of US states.
Users can experience uncontrolled laughter, a temporary inability to speak, dramatic visual and auditory hallucinations, uncoordinated movement, a feeling of being out of the body and a wide range of other unsettling phenomena.
In the US, following the suicide of a teenager last year who had at some point smoked the plant, there were calls for a federal ban.
Here, Labour MP for Bassetlaw, John Mann, recently tabled an early-day motion demanding the government urgently rectify its "oversight". "Some claims made about salvia are very bad. People will be shocked by this," he said.
Source - BBC