The sale and possession of "magic" mushrooms was yesterday banned by Minister for Health Mary Harney.
The order, which has immediate effect, clarifies an ambiguity in current legislation, which makes it illegal to sell the hallucinogenic mushrooms if they are processed but not in their raw state.
After being agreed at yesterday's Cabinet meeting, Ms Harney introduced a regulation under the Misuse of Drugs Act to make it illegal to sell them in any form.
Ms Harney said yesterday that a meeting she had in December with the family of a young man who died after taking "magic" mushrooms made her realise the extent of the problem.
"At that time it had become clear that the sale of 'magic' mushrooms was increasingly commonplace, and I directed that legislation be prepared to clarify the law to ensure that the trade in these drugs could not continue. I have signed the statutory instrument required to give effect to that legislation today."
Liam Twomey, Fine Gael spokesman on health, said the ban clarified a confusing legal situation.
"What you have to ask with any drug is whether they are addictive, and 'magic' mushrooms have this addictiveness. Not everyone who takes them will die as a result, but there is the potential. I don't think any country in the world could allow that drug to be sold openly."
Gráinne Kenny, president of the Dublin-based Europe against Drugs (Eurad), welcomed the ban. "The gardaí have done their best before now, but their hands were tied. These are all hallucinogenic substances and they're very unstable. You don't know what effect they're going to have from person to person."
While the drug might remain on the black market, she said, it would now be socially unacceptable. "Before now, people said, 'sure they can't be harmful, they're legal'. There's so much ignorance and apathy out there. I welcome them being banned. If they are pushed underground, at least the gardaí have a free hand to prosecute."
Bríann O'Connor, co-owner of Ireland's largest chain of "magic" mushroom shops, Irish Head Stores, said the ban was "ridiculous".
In July 2005, he said, he received a letter from Minister for Justice Michael McDowell confirming that it was not an offence to possess or sell raw mushrooms. Despite this, he and his staff had been arrested several times in recent years.
"If this only became illegal at 4pm today, then why was I arrested all those times, and why did the gardaí confiscate €20,000 worth of my stock?" he said.
Last week, Helen Stone, who runs the Funky Skunk shop in Cork city, failed to secure a High Court order stopping Customs officers from seizing shipments.