A runny nose is best cleared by blowing the nose and antibiotics should be strictly avoided, say researchers. Doctors often prescribe antibiotics for respiratory tract infections when nasal discharge is purulent containing pus.

“They are probably effective, but they can cause harm and most patients will get better without them,” said University of Auckland researchers who reviewed seven studies on the use of antibiotics for a runny nose, reported online edition of BBC News.

Antibiotics benefited only one in seven people as the runny nose would normally clear up by itself, with coloured discharge — a common feature of colds.

They found antibiotics can often have side-effects, including vomiting, diarrhoea and abdominal pa-in, researchers said in the British Medical Journal. “Antibiotics should only be used when symptoms ha-ve persisted for long.” Doctors should only prescribe antibiotics in a few exceptional cases. The best advice to give is to keep blowing your nose to get rid of the virus, they said.