To most people, the idea of charging a dime bag to your Visa might sound like a half-baked scheme from Pineapple Express. But that was a reality in California until recently.

Now, with pressure from the federal government, medical marijuana is set to become a cash-only business throughout the state.

SF Weekly's "The Snitch" blog reports that merchant service providers -- the middle men that process credit card transactions between vendors and companies like Visa and Mastercard -- are being strong-armed into refusing payments from pot dispensaries starting this month.

Stephen DeAngelo, executive director of the Harborside Health Center, a marijuana dispensary in Oakland, Calif., told the East Bay Express the push from the credit card companies is likely the result of pressure from the U.S. Treasury Department.

The new policy would be consistent with a wider federal crackdown on marijuana dispensaries, which has included high-profile raids, including one in Oakland that seized more than $1 million in cannabis in April.

While some Bay Area dispensaries have always been cash-only, some are concerned that the new rules may marginalize low-income consumers, or heighten the risk associated with procuring medical marijuana.

"A medical marijuana customer is now a guaranteed cash-carrying target for petty criminals," SF Weekly wrote.

California is not the only state that allows patients to purchase medical marijuana, but it has been the center of recent controversy about the drug's legality.

In October of last year, a California appeals court struck down a permit system used by the city of Long Beach to control pot distributers. While reprieves were initially granted to 18 collectives, the Long Beach City Council voted down a crucial extension, a move that could doom the city's legal pot industry, according to the Contra Costa Times.