Antibiotics does little help for people with sinus infections and its overuse is warned against by US researchers in Wednesday's Journal of the American Medical Association.

A new study in journal found that the antibiotics doesn't ease the symptioms of patients with acute uncomplicated rhinosinusitis any sooner than an inactive placebo pill.

"There is not much to be gained from antibiotics," said Jane Garbutt of Washington University School of Medicine in St. Louis, who led the study.

The study involved 166 adults with moderate, severe or very severe symptoms such as sinuses and nasal discharge.

In the study, participants were found showing signs of benefit from the antibiotic after seven days, but the effect was small and had vanished another three days later.

After 10 days, 78 percent of the people on antibiotics and 80 percent of the placebo-treated people said they felt a lot better or no longer had symptoms.

Sometimes it is hard for doctors to tell whether the sinus infections are caused by bacteria or by a virus, in which case antibiotics are useless.

Fewer than two percent of sinus infections are bacterial, said Anthony Chow, an expert in infectious diseases at the University of British Columbia in Vancouver, Canada.

Chow said most cases are viral and the vast majority don't require antibiotics, warning that antibiotics has been abused, so there is a need to be more cautious in prescribing them and to hold back.

Rather than giving antibiotics, the researchers suggest treating symptoms along with watchful waiting to see whether further treatment is necessary.