"Idealisms is not exist in this life"
Everything have its undesirable effect. We should only realize that and deal with this fact well.
Even your medicine that includes antibiotics has this undesirable effect which is called side effects.
In addition to work against microbes. It causes Rash, diarrhea, Upset stomach and Fungal (yeast) infections like thrush.
Realizing that makes you deal with these effects on using Antibiotics