This is the Data Quality Act on Drugs:

Americans for Safe Access, an organization that promotes the legalization of medical marijuana, is launching a legal challenge against the federal government's claim that marijuana has "no currently accepted medical use." According to this story, ASA is using the Data Quality Act to challenge the scientific basis of such statements, in an effort to force the federal government to acknowledge the value of medical marijuana.

This could be an interesting test case for the judicial enforceability of the DQA. The law creates procedures to ensure the accuracy and reliability of scientific and technical information upon which federal government decisions are based. Enacted in 2000, it has been viewed primarily as a tool for industry to use to challenge the scientific basis of government regulations. If ASA is successful in their suit (and they have to overcome a challenge to their standing to sue), the DQA may be viewed in a different light.

More information about the lawsuit it available here. For the Science editorial on the suit, see here.