RALEIGH, N.C. — A

state law

that restricts the sale of some cold medications to crimp the production of illegal methamphetamine took effect Sunday.

Consumers now must request medications that contain pseudoephedrine, such as Sudafed, at a pharmacy counter. Buyers also must provide proof that they are at least 18 years old and sign a log that can be turned over to law officers hoping to spot buyers who travel from store to store to stock up on the ingredient. Sales are limited to only two packages at a time.

The law was approved in the General Assembly last year to cut into the growing production of methamphetamine in North Carolina. In 1999, the first year that meth labs were reported in the state, authorities discovered nine labs. Last year, investigators found 328 amateur labs.

The law is based on one passed in Oklahoma in 2004 that helped reduce the production of meth in that state by 80 percent, the state Justice Department said.

"Putting these products behind a pharmacy counter is a small price to pay to protect our communities from these potentially deadly drug labs," Attorney General Roy Cooper said in a statement.

A similar law took effect on Sunday in Illinois, where state police have seen the number of meth lab busts climb from 24 in 1997 to nearly 1,000 in each of the past three years.

Oregon started a registry for cold remedies containing pseudoephedrine and saw its methamphetamine lab discoveries dropped by more than half last year.