Having your credit card refuse to cover your medical marijuana purchase? Priceless

If you’re about ready to refill your supply of medical marijuana, you might want to stop by an ATM first.

In the past few days, a number of Bay Area dispensaries have told their clients that from now on it’s cash only, because Visa and MasterCard aren’t allowing their cards to be used for marijuana purchases anymore.

“Visa and MasterCard are now refusing to accept your credit card charges for your medicine at many Bay Area dispensaries. We are working diligently to address this issue quickly,” Vapor Room, a Haight Street dispensary, told members Sunday.

Harborside Health Center in Oakland sent its patients a similar message, blaming a “continuing federal threat of seizure against financial institutions.”

In fact, Harborside, the largest medical marijuana dispensary in the country, is facing a federal seizure threat of its own. On Wednesday, it was served notice from the U.S. attorney’s office in San Francisco that its facilities in Oakland and San Jose are subject to forfeiture because they are being used to “distribute and cultivate marijuana.”

Although marijuana for medical use is legal in 17 states plus the District of Columbia, it remains verboten as far as federal law, and the feds continue to take a dim view of commerce surrounding the practice.

“This has been going on for at least two years, with major financial institutions purging medical marijuana dispensaries from their transactions,” said Kris Hermes, a spokesman for Americans for Safe Access, a national advocacy group based in Oakland.

For its part, San Francisco’s Visa said Wednesday, “Visa has not changed its policy. Our policy is that Visa cards should only be used in connection with legal transactions. We do not allow the Visa payment system to be used for any illegal activity and have banned illegal transactions on Visa cards. Merchant banks, also known as acquirers, are responsible for ensuring that their merchant customers comply with all applicable laws.”

Calls and e-mails to MasterCard were not returned.