A synthetic drug named after reggae icon Bob Marley will be banned in Victoria after it put five people in intensive care.
Marley, designed to copy the effects of cannabis, will be banned from Tuesday, with those caught trafficking it facing up to 15 years in jail.
Anyone caught possessing the synthetic drug faces up to one year in jail under laws unveiled by the state government on Saturday.
Retailers, including shop staff, also face stiff criminal penalties if they don't know exactly what they are selling.
The crackdown comes after five people were hospitalised in intensive care during the past week after smoking the substance.
Their symptoms included loss of consciousness, seizures, agitation and difficulty breathing.
Mental Health Minister Mary Wooldridge says retailers who sell synthetic drugs are dicing with people's health and their own future.
"This is a poison, it's a drug of dependence and it's very dangerous. That's why we're instituting this ban," she told reporters on Saturday.
Ms Wooldridge said the substances were manufactured in secret labs and their ingredients were often not known in detail but the health effects were dramatic.
"These are marketed as legal highs but what I very clearly want to say is they're poison."
The government will introduce the new laws using powers it introduced in 2011 to declare a substance a poison if it poses a significant health risk to consumers.
The laws will come into effect on Tuesday, following the Victorian Governor's endorsement.
