DUBLIN, Ireland ─ It started with an explosion that destroyed the Nirvana shop in Dublin’s Capel Street on Feb. 12.

Five days later a Molotov cocktail was thrown into the Happy Hippy store in North Frederick Street.

Since then seven retail outlets with similar exotic names have been attacked with incendiary devices in different parts of Ireland, the latest being the Magic Bus Stop in Dundalk on April 15.

They are all so-called "head shops," which specialize in the sale of legal drugs and associated paraphernalia. There are 70 such stores in the Republic of Ireland, and clearly some organization or group of citizens wants to put them out of business.

The head shops' products have become something of a craze among Ireland’s middle-class youth. This makes them lucrative business ventures in recession-hit Ireland. In a two-hour period on a recent Friday night, a television crew recorded 400 young customers lining up at a head shop to pay an average of 40 euros ($53) for drugs with names like Snow Blow and Wild Cat. These substances often contain mephedrone, a chemical in white powder form that mimics cocaine and is completely legal in Ireland.

The head of the Irish police's national drug squad, Tony Quilter, said the force monitors the head shops and so far has found only four selling illegal drugs. The police do not know who is behind the attacks on the head shops, Quilter said. The chief suspects include local drug dealers who are losing business or vigilante groups worried about the effect of the shops on their neighborhoods.

As the public becomes increasingly concerned about the legal drug trend, the Irish government is rushing to prepare a bill to criminalize the sale of legal highs. It has fallen behind the rest of Europe, where 14 countries have introduced measures to control the sale of such substances, with varying degrees of success. A ban on mephedrone came into effect in Great Britain and Northern Ireland three weeks ago, giving a new dimension to cross-border shopping.

But lawmakers will have a hard time keeping up. Twenty-four new, legal, chemical-based drugs emerged in Europe last year to satisfy a continent-wide demand for synthetic highs, according to a report from the European Monitoring Centre for Drugs and Drug Addiction. Nine of these are marketed as plant foods or spices but can be smoked to give a similar effect to cannabis.

Mephedrone has been linked to a number of deaths in other countries, and much publicity has been given to the case of a young Dublin man, Daryl Smith, who tried to commit suicide after taking an overdose. Smith was waiting at a bridge to jump under a train and then tried to stab himself with a screwdriver. The 19-year-old student is typical of educated teenagers who would never buy illegal drugs but regularly get high on mephedrone.

With the proliferation of new drugs, the Irish minister for community affairs, Pat Carey, wants to prohibit head shops operating as legal entities. Banning the substances may not be enough, he argues. According to the Monitoring Centre report, suppliers easily circumvent drug controls by offering unregulated alternatives. The composition in terms of synthetic additives is constantly changing to evade control measures, and new packaging appears all the time.

Irish Justice Minister Dermot Ahern agreed that one of the problems of banning a substance was that a variation of that product could be quickly introduced. He is aiming to change the law “to deal with the issue from a criminal justice point of view, as well as from a health point of view.” But some members of Ahern's own Fianna Fail party sharply disagree. Parliament backbencher Jim McDaid said his approach would be a huge mistake, as it would allow criminal gangs to take over the businesses.

Because of the adverse publicity they have received recently, some head shops have begun distributing leaflets offering home delivery. In some parts of Dublin it is now as easy to get artificial cocaine or cannabis delivered to your door as it is to order a pizza.