Montevideo: Uruguayans will be able to choose from three varieties of state-sanctioned cannabis when marijuana starts being sold in pharmacies in the small South American country next year, the National Drug Board said Saturday.

Each variety will have different levels of the mind-altering compound tetrahydrocannabinol (THC) and cannabidiol (CBD), believed to soften the impacts of THC, said the board's president, Milton Romani.

Visitors take pictures of themselves with a marijuana plant during the Expo Cannabis Fair, the second of its kind after Uruguay legalised marijuana production and sales. Credit:AP

"There will be three options with indications about the effects of each that point beginners toward starting with the lowest level" of THC, Mr Romani said on the sidelines of the marijuana forum Expocannabis 2015.

Mr Romani declined to specify the names of the three varieties.