The National Poisons Information Centre has received 34 calls from emergency departments in the past two months in relation to people hospitalised after taking legal highs, compared to less than 10 calls over concerns with legal substances in a 12-month period between 2008 and 2009.

This massive upsurge in calls to the poison centre based at Dublin's Beaumont Hospital is in line with an increase in the number of headshops opening around the country.

From April last year until March, it received 62 calls from hospitals. "A lot of the symptoms people are presenting with are racing hearts, chest pains, heart palpitations and extreme agitation," John Herbert, a specialist at the centre told the Sunday Tribune.

"We have been monitoring these substances since the ban on BZP was brought in. Often, the hospitals give us the name on the packets of whatever the person has taken and we then advise them on supportive therapy treatment. The number of calls has been steadily increasing over the past 12 months and the most dramatic rise has been in the past two months."

Herbert added that most people presenting to hospitals had taken legal highs derived from methcathinone, a stimulant from which mephedrone is derived.

"These substances can be toxic. There has been so much publicity around headshops recently also, that advertising is probably leading to more people taking them.

"A couple of years ago, hospitals were dealing with a lot of people who'd taken too much cocaine. Things have changed now. When there's a drop-off in use of one drug, there's always a pick-up in another substance."

In the same 12-month period in which the poison centre received 62 calls from hospitals about legal highs, it received just 25 calls about people suffering adverse side effects from cocaine. Two years previously over a 12-month period, the centre received 70 calls in relation to cocaine.

It emerged on Friday that gardaí are to be given new powers to allow them shut down headshops.

The powers will be included in a new criminal justice bill, which is being drafted by senior officials from the Department of Justice and the Attorney General's office.