Ketamine users on health problems caused by drug
21 July 2011 Last updated at 09:08 BST
A review into the horse tranquillizer ketamine by the Independent Scientific Committee on Drugs says that recreational use of the drug appears to be a growing problem.
Although it is not calling for ketamine to be reclassified, the committee suggests that the drug is wrongly classified as being less harmful than ecstasy and cannabis.
Ketamine is now the fourth most popular recreational drug in the UK and in extreme cases, use of it can lead to severe bladder damage as well as other health problems.
The BBC's Chris Buckler went to meet some ketamine users living in a squat in Bristol, to hear their stories.