US researchers do not need a second federally approved facility for providing research-grade cannabis, the Drug Enforcement Administration (DEA) has ruled. The decision ends an eight-year bid by Lyle Craker at the University of Massachusetts in Amherst, to grow cannabis for medical research, which was supported by the Multidisciplinary Association for Psychedelic Studies (MAPS). A single laboratory at the University of Mississippi supplies cannabis under a contract with the National Institute of Drug Addiction.

Craker, MAPS and others have argued that the current supply of cannabis is of inconsistent quality, difficult to obtain, and that efforts to widen that supply are being stalled for political reasons (see _Nature_ 430, 492; 2004). In 2007, a DEA judge recommended that Craker's application to set up a second facility should be granted; but the DEA's final ruling, made on 7 January, said the current supply was adequate.