Voters in Oklahoma approved a ballot initiative to legalize medical marijuana on Tuesday.

It's one of the least restrictive medical marijuana laws in the country, allowing doctors to recommend the drug to anyone over the age of 18.

Oklahoma residents voted for 56-43% in support medical marijuana.

Voters in Oklahoma approved a ballot initiative to legalize medical marijuana on Tuesday.

The ballot initiative, State Question 788, will be one of the least restrictive medical marijuana models in the US once it becomes law. It will allow doctors to recommend medical marijuana to anyone over the age of 18 and will legalize growing marijuana for medical purposes in the state.

Oklahomans overwhelmingly supported the ballot initiative, approving medical marijuana legalization 56%-43%.

A group opposed to medical marijuana spent $815,000 in a campaign to defeat the ballot initiative, and the Oklahoma State Medical Association spent a further $95,000 against the initiative, according to Cannabis Wire.

Oklahoma's conservative electorate seems to be coming around the issue, PBS reports.

"Some people said I couldn’t be a pastor and support medical marijuana, but I would say most of the people I know, including the Christians I pastor, are in favor of it," Danny Daniels, a conservative Evangelical pastor, told PBS.

Medical marijuana is legal in some form in 29 states, and the Food and Drug Administration recently approved a marijuana-based drug, Epidiolex, to treat childhood epilepsy.

The federal government still considers marijuana a Schedule I drug.

Another red state, Utah, is weighing a medical marijuana ballot initiatives this year, and Michigan residents will vote on legalizing the drug outright in November.

This story has been updated.