But customers are saying the standard decongestants such as Sudafed, Actifed and other products with the "ed" suffix don't seem to be working.

Since a federal law took effect last year, cold and allergy medicine containing pseudoephedrine must be stored behind drugstore counters, and people can buy only a limited amount.

The major pharmaceutical companies came out with newer products, such as Sudafed PE, which have a different active ingredient, phenylephrine.

But critics say it's a weak substitute.

"We have patients who have commented that the older formulations with pseudoephedrine are more effective," said Ron Toy, a pharmacist in Modesto, Calif.

Some sufferers have moved to antihistamine tablets, which don't contain pseudoephedrine.

For years, illegal drug labs extracted chemicals from store-bought medicine to cheaply produce methamphetamine, an addictive stimulant that has left a trail of ruined lives across the United States.

Congress approved the Combat Methamphetamine Act of 2005 to cut off the supply of these ingredients to meth makers. Since it was signed into law in March 2006, medicines containing ephedrine, pseudoephedrine and phenylpropanolamine must be sold from behind pharmacy counters.

Customers have to show identification, and sales are recorded in a logbook, including the date and quantity of the purchase. Sales are limited to 9 grams per month, which is about 360 tablets -- about eight per day.

Toy said he agrees with the law. But not as many customers are going through the trouble of buying the pseudoephedrine products. The law, he said, has "created a barrier."

His store's pharmacy technicians attended training to learn about the guidelines and use reference sheets to tell whether customers have exceeded their limits.

Federal officials say they see positive signs in the fight against meth, including fewer labs operating in the United States and a 20 percent decrease in longtime use of the drug since 2002.

Unfortunately, it has resulted in more law-abiding citizens with bloodshot eyes and runny noses who are desperate for something to relieve their allergy symptoms.

Dr. Wallace Carroll, an allergist, said the newer decongestants usually don't work as well, although some people may respond to them.

He isn't a big fan of decongestants, however. "They raise blood pressure, and people feel wired with them," he said.

Patients in their 50s and 60s should be wary of products that boost their blood pressure, and decongestants have been associated with strokes in older people, he said.

Carroll advises patients to use nasal rinses with salt water or prescription nasal sprays. Allergy shots, reserved for people with the worst symptoms, are also an option.

Not many patients have complained to him that pseudoephedrine was taken off store shelves, he said.

"They are probably seeing the allergist because whatever they are doing isn't working."