Listening to loud music exacerbates the effects on the brain of taking ecstasy, researchers have found.
Ecstasy is linked to dance culture
Italian scientists gave the drug to rats who were then exposed to music at nightclub noise levels.
The researchers measured the electrical activity in the rats' brains and found that noise prolonged the effects of ecstasy by up to five days.
Experts said the study, published in the Biomed Central Neuroscience, showed music worsened users' "comedown".
Ecstasy is usually taken by clubbers - who are in an environment full of flashing lights and loud music.
The drug produces feelings of euphoria and energy, and a desire to socialise.
But there is mounting evidence from both animal and human studies that it may damage nerve pathways in the brain. Long term use has been linked to memory loss and depression.
Experts have suggested that loud music may also affect higher brain functions.
The researchers, from the Institute of Neurological Science in Catanzaro, found low doses of ecstasy did not modify the brain activity of rats if no music was played.
But total electrical brain activity in the animals significantly decreased in the presence of loud music, selected to mimic levels commonly found in clubs.
High doses of ecstasy reduced brain activity even without noise, but the effect was enhanced by loud music and lasted for up to five days after the drug was administered.
In rats given a high dose of ecstasy but not exposed to music, brain activity returned to normal in one day.
Dr Michelangelo Iannone, who led the research, said in BMC Neuroscience that the effects of the drug could be made more potent "by relatively common environmental factors" and stressed the "potential danger for man of substances that have been so 'popularly' accepted as relatively 'safe' owing to their 'short term' effects."
Martin Barnes, chief executive of the drugs information charity DrugScope said: "Ecstasy is very much associated with the clubbing and dance scene and users report a heightened sense of awareness and a greater appreciation of music and their surroundings.
"After taking ecstasy users may feel tired and low and this may last several days leading to a 'mid-week hangover'.
"Short-term memory can be impaired and there is emerging evidence that prolonged use can lead to periods of depression.
"This research suggests that exposure to loud music may worsen the comedown but it is unclear how this may contribute to longer term effects."
Ecstasy was first synthesised in 1910. It was patented two years later by the German company Merck Pharmaceuticals as an appetite suppressant.
It was first seen in Britain as a recreational drug from the US in the mid-1980s, but has been illegal in the UK since 1977.
In the early 1990s, ecstasy tablets cost up to £20 each. Last year their price was reported to have dropped to as little as 50p.
Home Office figures published in October last year showed that an estimated 2m people aged 16 to 59 had used ecstasy in their lifetime, and 556,000 had used it in the previous month.
Around 10 deaths are linked to ecstasy use each year.