The Health Service Executive has warned that new bugs are emerging that are multi-resistant.
People are being advised to avoid taking antibiotics for a flu or cold, as the HSE said they will get better.
A new website called undertheweather.ie has been set up to give advice on how to treat viral infections.
The HSE said rest, fluid and paracetamol is all people need to get over many of these illnesses.
Dr Philip Crowley, HSE National Director for Quality and Patient Safety, said: "Undertheweather.ie is part of our ongoing work to tackle the global threat of overuse of antibiotics, and the fact that antibiotics are becoming less and less effective.
"The common conditions included in the site are almost always caused by a virus, so an antibiotic is useless in dealing with these illnesses.
"We want to support people to know what to do when they are unwell, and when to get advice from a health professional, but also that antibiotics are almost never the answer when it comes to these common complaints."
