Users of designer drugs - created in labs to mimic the make-up of banned substances such as Ecstasy and amphetamines - suffered such extreme side-effects that they had to be sedated.
They had also been treated for paranoia, psychosis, high heart rates and raised blood pressure, he said.
"Users are playing Russian roulette. They are buying substances marked as research chemicals. The implication is that you should do the research on yourself to find out whether they're safe or not. This is a totally uncontrolled, unregulated market."
The first large quantities of legal highs, or psychoactive drugs - many made in China - appeared in Britain two years ago.
They can be easily bought online or from shops selling drug paraphernalia and herbal goods. Some undergraduates also sell them to fellow students.
The council said: "Many people importing these new substances appear to have had no previous involvement in the illicit drug trade and are just in it to make a quick buck."
Ministers have outlawed several such substances, but the council warned that producers were sidestepping the bans by tweaking the composition of drugs.
It backed creating a new system of broader bans in which all substances chemically similar to controlled drugs were automatically made illegal.
The council also called for suppliers to have to demonstrate that legal highs were not being produced for human consumption and for a fresh drive to alert the public to their dangers.
Roger Howard, chief executive of the Drug Policy Commission, backed the recommendations. "It's increasingly difficult for police to identify the different drugs they are finding," he said.
The Home Office said it was considering the proposals.
- Independent
