There has been a rise in the number of young people taking the Class C drug ketamine, a charity warns.
DrugScope found users experimenting with stronger doses, including injecting the drug which increases infection risk from shared needles.
Increased use was found in nine out of 20 studied areas: London, Birmingham, Newcastle, Ipswich, Bristol, Blackpool, Portsmouth, Nottingham and Sheffield.
The Home Office said use of the drug would continue to be monitored.
Ketamine was made illegal three years ago after a surge in the number of people using it as a recreational drug.
It is legal in low doses for medicinal use as an anaesthetic and a horse tranquiliser.
The investigation by DrugScope's magazine Druglink uncovered evidence that people were experimenting with larger amounts of ketamine as the price of the drug fell.
A gram had dropped in price by a third during the past three years and now cost £20 - half the price of a gram of cocaine.
Also known as K, Special K and Vitamin K, the drug has a strong following on the dance scene.
Usually it is snorted or swallowed but the charity discovered more people were injecting it in an attempt to experience stronger hallucinations, which increases the risk of infection from dirty needles.
At low doses the user may feel euphoric, experience waves of energy, and possibly synaesthesia - sensations such as seeing sounds or hearing colours.
At higher doses the user might become paralysed, experience hallucinations and alternate realities, and a feeling of disassociation giving an out-of-body experience known as the "K-hole".
The researchers found that ketamine use was on the rise in nine out of 20 areas surveyed, although it remained low when compared to cannabis, cocaine and ecstasy.
Ketamine was linked to the deaths of 23 people between 1993 and 2006. Most had accidents after taking the drug.
DrugScope chief executive Martin Barnes said young people underestimated the dangers they took when using the drug.
He said: "Ketamine's harms increase considerably at high doses and injecting users risk exposure to blood-borne viruses such as Hepatitis C or HIV."
A Home Office spokesman said: "While findings from the British Crime Survey show that less than half of 1% of all respondents reported the use of ketamine in 2007/08, and that there was no statistically significant change in this figure compared to the previous year, it is a dangerous drug that can cause serious harm to those who do use it."