Don't expect the company will have it easy. As far as the federal government is concerned, marijuana has no place in medicine. The Drug Enforcement Administration considers marijuana—like heroin and LSD—a schedule I controlled substance. Schedule I drugs are likely candidates for abuse, with no recognized therapeutic benefits. (Cocaine is a schedule II. Cough syrup is a V.)

Yet the medical use of marijuana by Americans is spreading. Fourteen states and the District of Columbia allow patients to use marijuana—and in some states to grow it—for medical purposes. Shops legally sell medical pot in California, Colorado, and New Mexico. But federal prosecutors continue to target growers, distributors, and users even in states where medical marijuana is legal.