Walgreen Co. (WAG), the nation's largest drugstore chain, Friday said it will move all products containing pseudoephedrine (search) — used to make methamphetamine — behind the pharmacy counter in all stores nationwide by the end of October.

Pseudoephedrine is found in cold medicines such as Sudafed, NyQuil and Tylenol Cold, and can be used to make the highly addictive, illegal drug.

A growing number of retailers, including Target Corp. (TGT), CVS Corp. (CVS), and Albertsons Inc. (ABS), as well as many state legislatures, are restricting the sale of over-the-counter cold medicines, in an effort to help law enforcement tackle the growing national problem of methamphetamine addiction.

A bill to limit access to pseudoephedrine nationwide has been approved by the Senate Judiciary Committee and a similar one is pending in the House of Representatives.

Methamphetamine (search) can be made using common household and agricultural ingredients following recipes easily found on the Internet.

According to a survey of law enforcement organizations conducted by the National Association of Counties and released in July, 58 percent of county law enforcement agencies now see meth as their largest drug problem.