The number of patients in Northern Ireland taking antibiotics has gone down by 12% in seven years.
Health experts believe they are winning the battle to stop people automatically asking for the drugs when ill.
Microbiologist Dr Hugh Webb of the Royal Victoria Hospital said new findings showed antibiotics were not always the best treatment.
"We have to encourage doctors and patients to use antibiotics only when they are really needed," he said.
While acknowledging the important role played by antibiotics, Dr Webb said there was a "downside".
"We are promoting resistance to bugs which will not respond to antibiotics in future," he said.
"That is a major public health issue."