Sales of recreational marijuana began this week in Canada, NPR reports. Anyone over the age of 18 is allowed to possess less than 30 grams (just over an ounce) of the drug.

Canadians also are permitted to grow up to four marijuana plants in their home, and to buy from a provincially regulated retailer, the article notes. The Canadian government will oversee marijuana production and manufacturing. Provincial and municipal governments control wholesaling and can set laws on public consumption.

Canadian Deputy Prime Minister Anne McLellan said early tax revenues from marijuana sales will be used to research addiction treatment. They also will be used for mental health resources and treatment, and for public education about the drug.

Canada is the second nation to legalize recreational marijuana. Uruguay legalized marijuana in 2013.