New laws aimed at putting head shops out of business are to be introduced by the government in the Republic of Ireland.
Under the proposals, anyone convicted of selling psychoactive substances which mimic the effects of illegal drugs, could face five years' jail.
Head shops specialise in selling legal alternatives to banned substances such as cocaine, cannabis and ecstasy.
But concerns about the health effects of these drugs led to a ban in May.
This forced many of the head shops to close. But within a few weeks, 48 head shops had reopened selling different products.
The new legislation makes it illegal to sell or supply any psychoactive product.
Minister for Justice Dermot Ahern said the aim was to put "head shops" permanently out of business