Like plenty of hale and hearty young Irishmen, Chris knows just how to unwind after a tough day at the office: He reaches for his bath salts.

He gets the water ready -- but in a glass, not the tub. Then, despite a warning on the box that it’s “not for human consumption,” he pops a capsule in his mouth and downs it with a swig.

For the next few hours, he’s happy and hopped up, full of energy for an evening of clubbing, without a hangover lying in wait.

“I find it much less debilitating” than alcohol, confides the 29-year-old bookkeeper, who can pop two or three capsules a night. He asked that his full name not be used.

Such “bath salts” are popular these days throughout Ireland, not for a relaxing soak at home but because many contain a party drug known as mephedrone. They’re part of the literally dizzying array of products being sold in stores offering customers cheap and legal highs, stuff marketed as bath salts or incense but designed to be smoked, snorted or swallowed.

The new-wave head shops are fast becoming a fixture in this island nation, multiplying with astonishing speed from just a few several years ago to as many as 100 today. Much of the growth has occurred in the last 12 months, even as the rest of the Irish economy underwent a painful contraction.

Authorities are increasingly concerned about the potential effect of head shops and their products on crime and the nation’s health. Parents, too, are worried about their children’s exposure to substances that mimic the effects of outlawed drugs such as cocaine and marijuana.

Officials are groping for ways to limit, regulate or ban head shops, which operate with so little restriction that many stay open till 4 a.m., supplying eager clubbers through metal hatches in their doors, like shady pharmaceutical take-aways. By contrast, the sale of alcohol is far more regulated.

That the head shops aren’t subject to heavier control is due in large part to clever packaging. By peddling products advertised, however misleadingly, for other uses, the stores avoid strict food and drug safety regulations and receive virtually the same treatment as retailers that sell clothes, books, home furnishings or other “harmless” consumer goods.

The charade fools no one, of course, least of all the manufacturers, who indulge in some sly descriptions on their labels. The makers of Snow “bath salts,” for instance, inform buyers that adding their “fine white powder” to the bath will make them chatty and peppy, but warn against the presence of heavy machinery in the bathroom.

“They’re labeled as ‘not for human consumption,’ but when you go into the shop, you’re told how to consume it, how to inject it,” lawmaker Joe Costello said. “We have a range of substances that are sold that really are not regulated, that nobody knows precisely what’s in them, nobody knows the quantities that are being sold or taken.”

Some insalubrious consequences are already beginning to emerge.

Hospitals have reported an increase in the number of emergency room patients suffering from hallucinations, panic attacks and delirium brought on by mind-altering products such as Ivory Wave, which is sold as bath salts.

Here in the Irish capital, residents and businesses were alarmed last month by fires believed to be arson at two head shops, possibly set by drug dealers angry about the competition.

Even so, Costello is leery of banning the shops, which many fear would drive up the illegal drug trade and open the door wider to gangs and organized crime.

The government decided this month to outlaw a range of substances found in head shops, including mephedrone, which mimics the effect of ecstasy; the ban will take effect in June. But targeting specific substances can also be an exercise in frustration, triggering an endless cat-and-mouse game in which manufacturers keep tweaking their products to stay one step ahead of the law.

Costello has settled on a softer approach: He’s pushing a bill in the Dail, the lower house of parliament, that would subject head shops to more planning controls, which could at least help limit where they can open -- for example, not too close to schools.

Shane O’Connor, director of a chain of head shops, sees some sense in that. In fact, O’Connor says he’s open to stricter guidelines on window displays and a ban on sales to anyone younger than 18.

It’s the idea of closing down the shops that he finds absurd.

“Prohibition doesn’t remove demand,” he said. “The only way to remove demand for illegal drugs is to offer safer legal alternatives.”

In many ways, today’s head shop craze is merely an extension of a wave of drug use that has swept Ireland since the 1970s.

Heroin and other hard drugs were popular in the beginning. Then cocaine and crack started making inroads, especially during Ireland’s economic boom of the last 20 years, which transformed the Emerald Isle into the Celtic Tiger.

Now recreational users have an expanded menu of drugs to choose from, at much lower, recession-friendly prices.

“It’s a lot easier now,” said Thomas, 19, a slightly scruffy college student who declined to give his last name. “It’s all legal at the moment.”

He had just bought a packet of Ice Gold, an “aromatherapy resin extract” by a company engaged in “botanical research.” Two grams cost about $35. Thomas buys a packet a week to take home and smoke; he no longer has to badger friends for pot. (Online discussions say Ice Gold contains resin from cannabis, but shop workers insist that it “has no cannabinoids.”)

Nothing on the box, though, says exactly what’s in Ice Gold or how to use it safely. There’s only an effusive, but not particularly helpful, description of how such plant extracts “have for millennia been used in shamanic rituals.”

That lack of information upsets Christopher Luke, a vocal critic of head shops in the southern city of Cork, where a store called the Funky Skunk sits on one of the main shopping drags.

An emergency room doctor, Luke has seen some of the ugly outcomes of unregulated drug use.

“The consequences of head shop products are sometimes spectacular in terms of psychosis, delirium and what they need in terms of treatment,” he said.

His hospital admits a head shop case every week to 10 days, adding to the strain on Ireland’s overburdened healthcare system, Luke said.

“Head shop drugs are in every village and town of this island,” he said. “Even if 1% of consumers come to harm, it could be very, very difficult.”

Like others, Luke counsels against rushing through inadequate or ill-thought-out legislation to deal with the situation.

But Costello, the lawmaker, said some stopgap measure needs to be taken now, especially if Ireland wants to avoid turning into a destination for the legally blissed-out.

“We leave that type of tourism,” he said, “to Amsterdam.”

henry.chu@latimes.com