AMSTERDAM (Reuters) - The Netherlands will ban the sale and cultivation of all hallucinogenic “magic” mushrooms from next week, the latest target of a country seeking to shed its “anything goes” image.

The Dutch government proposed the ban in April, citing the dangerous behavioral effects of magic mushrooms following the death of a French teenager who jumped from an Amsterdam bridge in 2007 after consuming the hallucinogenic fungus.

“The use of magic mushrooms has hallucinogenic effects. It is proven that this can lead to unpredictable and therefore risky behavior,” the Dutch Health Ministry said in a statement.

A challenge to the ban was rejected by a court in the Hague on Friday. From December 1 the production or sale of fresh magic mushrooms could lead to a maximum jail sentence of four years, a spokesman for the Dutch Justice Ministry said on Friday.

“We are targeting the growers and the shops who are selling the mushrooms,” the spokesman said.

The active ingredient in magic mushrooms is psilocybin. Effects last up to about six hours and can include nausea, vomiting, muscle weakness and drowsiness in the early stages after consumption.

The psychological consequences of psilocybin use include hallucinations and an inability to discern fantasy from reality. Panic reactions and psychosis also may occur, particularly if a user ingests a large dose, according to the U.S. Justice Dept’s National Drug Intelligence Center.

Some proponents of magic mushrooms say that their use aids in spiritual awareness, gaining personal insight and meditation.

Selling dried magic mushrooms is already illegal in the Netherlands and carries a maximum jail sentence of eight years, the justice ministry spokesman said, but from next week a new ban will apply to fresh mushrooms which have been previously sold in so-called “smart shops.”

Staff in the stores, which stock mushrooms or “paddos” ranging from Thai to Hawaiian varieties for about 15 euros (about $20) a pack, said the ban will put users at greater risk.

“People will just go picking in the forest, and that can be dangerous. Or they will go to street dealers, and get mixed up with hard drugs,” said David Henriks from the Tatanka shop.

Posters in shops outlined the effects of different types of mushrooms, such as strong visual experiences or feelings described as “body highs.” They also suggested dos and don’ts of consumption, and rated the mushrooms for their intensity.

“It’s always safer to have the information before taking drugs,” said Roy Williams of the Innerspace shop, adding that in the past few weeks people had increasingly been buying “grow your own” mushroom kits in the lead-up to the ban.

The Dutch association of smart shops (VLOS) had tried to reassure authorities by promising tighter self-regulation and noted that most mushroom-related incidents involved young tourists mixing mushrooms with alcohol and cannabis.

On Friday the VLOS said it was highly disappointed with the court’s decision to reject the challenge to the ban.

“Under this government we have had a whole series of bans, and people have had enough of this,” said Paul van Oyen from the VLOS, adding that he would advise the board of the association to launch an appeal.

He said some of the 180 or so smart shops in the Netherlands would likely have to close because of falling turnover, and he expected to see a huge discount sale over the weekend as shops tried to get rid of supplies.

Figures from the Amsterdam emergency services show there were 55 call-outs for mushroom-related incidents in 2004, a figure which had more than doubled by 2006 to 128, with the majority of youngsters involved coming from Britain.

In recent years the Netherlands has dropped some previously tolerant policies and has tightened laws on drug use and prostitution.

Several brothels and sex clubs were shut down in 2008, city councils are planning to close marijuana-selling coffee shops near schools, while tobacco smoking and alcohol consumption in coffee shops have also been forbidden.