After reports of two apparent fatal overdoses, the Swedish health ministry said the country has asked the European Union for the right to speed up a ban on substances contained in a synthetic marijuana sold as "Spice".
The ministry said it had asked Brussels to class the products as drugs, based on a recommendation from public health authorities, which identified 24 cannabinoids and seven cathinones as dangerous substances.
The Swedish government "is seeking a speeded-up procedure, meaning that the time that the European Commission takes to handle the ban is cut to 10 days instead of the usual three months," the ministry said.
The Swedish media have carried near-daily reports on Spice since the deaths of a 22-year-old man and an 18-year-old man in separate cases in the last two weeks in what witnesses and police said were overdoses.
Synthetic marijuana, known as Spice or K2, Yucatan Fire, Moon Rocks and Bliss, contains the same active element as natural marijuana, but it is far more toxic.
Several countries have already tried unsuccessfully to stop the sale of synthetic marijuana, which is supposed to be burned like incense rather than smoked.
Sweden has one of the most repressive policies in Europe on cannabis. Swedish law allows convictions for the use of drugs in private homes once the presence of the drug has been confirmed by a urine test.