That's important because overuse of antibiotics can lead to drug resistance - which makes future infections more dangerous and harder to treat when the drugs are actually needed.

"The public needs to understand that antibiotics are not harmless," said Dr. Ralph Gonzales, the lead author on the new study from the University of California, San Francisco.

For bronchitis, he added, "We can reassure them strongly that (antibiotics) are not going to help at all and they'll cause harm." Along with contributing to resistance, antibiotics may also come with side effects, such as upset stomach and diarrhea.

At a large Pennsylvania health system where Gonzales and his colleagues conducted their study, about three-quarters of people with bronchitis were receiving prescriptions for antibiotics.

The researchers tested two different strategies to cut that number.

One-third of practices put up posters about when antibiotics are necessary and when they are not in each exam room and handed out educational brochures to patients. At another one-third of practices, nurses were electronically alerted to give patients a brochure when "cough" was one of the main symptoms entered in their chart.

The rest of the practices, used as comparison, didn't add any patient or provider education.

Gonzales and his team looked at close to 10,000 pre-experiment patient visits and just over 6,000 visits after the posters, brochures and alerts were put in place. All of the visits happened over the winter months.

The number of people with bronchitis getting an antibiotic stayed constant or inched up at practices that made no changes. However, it fell from 80 percent to 68 percent with the printed posters and brochures and from 74 percent to 61 percent with electronic reminders, the researchers reported Monday in JAMA Internal Medicine.

Those rates are still higher than researchers would like. But they show progress, Gonzales told Reuters Health.

"For practices that want to reduce their antibiotic prescribing for bronchitis, putting (posters) up in the exam room during cough and cold season would be a good idea," he said. (The posters can be found on the Centers for Disease Control and Prevention's website at 1.usa.gov/avrB7Q.)

Patients, he said, should have realistic expectations about how long their cough is going to last - on average, 10 to 14 days.

Appropriate treatments for bronchitis include cough suppressants and humidifiers. Sometimes there is another underlying problem - such as a sinus infection or reflux disease - that could be contributing to the cough, Gonzales added.

But as long as people don't have a high fever or trouble breathing, they can be confident they're not sick with something more serious or bacteria-related like pneumonia - and antibiotics are not needed, he concluded.

"Cough shouldn't be sufficient for someone to get an antibiotic," agreed Betsy Foxman, an epidemiologist who has studied antibiotic resistance at the University of Michigan in Ann Arbor but wasn't involved in the new research.

"You'd hate to be treating someone with a simple cough with an antibiotic that gives them a life-threatening disease, and that can happen," although it's rare, Foxman told Reuters Health.

She said patients can play a role in limiting drug overuse and resistance - because sometimes, doctors feel pressured to prescribe an antibiotic or are wary of taking a lot of time to explain why it's not needed.

"If the patients aren't demanding antibiotics, and they're questioning why they get one, then it's a lot easier not to prescribe one," Foxman said.

SOURCE: bit.ly/MbBLbb JAMA Internal Medicine, online January 14, 2013.

• A Permanent Economic Emergency