In a move intended to hamper production of illicit methamphetamine, the governor of Mississippi has approved a law requiring a doctor's prescription to buy any drug containing pseudoephedrine, the Associated Press reported Feb. 11.

The bill signed by Gov. Haley Barbour and effective July 1 makes Mississippi the second state after Oregon to make drugs containing pseudoephedrine available by prescription only. The chemical, which can be used as a precursor to methamphetamine production, is found in many cold medications.

Nearly 600 meth labs were seized in Mississippi last year. Pseudoephedrine drugs were available over the counter until a few years ago; now in most state they must be held behind the pharmacy counter but still can be purchased without a prescription, albeit in limited quantities.