Despite abundant evidence showing that antibiotics don’t work against viral infections, many doctors still prescribe them — especially amoxicillin or azithromycin (Zithromax) — for lower respiratory infections such as bronchitis, even after ruling out pneumonia.

That practice should change if medical practitioners follow the latest research published Wednesday in the journal Lancet. The European researchers randomly assigned amoxicillin or placebos to more than 2,000 patients diagnosed with bronchitis because of severe coughs, chest congestion, and other cold symptoms lingering for more than a week. They found that not only did antibiotics fail to alleviate or resolve symptoms faster than a placebo, but the drugs were more likely to lead to side effects including nausea, diarrhea, or rashes.