Antibiotics for Green Snot? Maybe

July 20, 2006 -- Last year they found no evidence antibiotics help head coldscolds. But now two New Zealand researchers say antibiotics "probably" help colds with ugly green mucus.

Even so, they still advise against the use of antibiotics unless symptoms last "long enough to concern parents or patients."

A runny nose with green mucus -- what doctors call "purulent rhinitis" -- is the most common reason for getting a prescription for antibiotics. After reviewing the scientific literature, Bruce Arroll, MBChB, PhD, and Timothy Kenealy, MBChB, of the University of Auckland in New Zealand, last year concluded the drugs don't work.

Now, after another look at the evidence, they've softened their stance -- just a little. Their most recent report appears in the current online issue of BMJ.

"Antibiotics are probably effective for acute, purulent rhinitis," Arroll and Kenealy now conclude. But, "most patients will get better without antibiotics, supporting the current 'no antibiotic as first-line ' advice."

In their review of scientific studies, the researchers found that people who take antibiotics when their noses keep running green for five to eight days have a slight (18%) chance of doing better than those who don't take the antibiotics.

At that rate, one of every seven to 15 patients would do better with antibiotic treatment. On the other hand, there's also a 46% higher risk of side effects -- usually diarrheadiarrhea.

What about people who cough up ugly green phlegm from a chest cold? So far, there's no proof antibiotics do a lot of good.

SOURCES: Arroll, B. and Kenealy, T. BMJ, Online First edition, July 2006.