The immune system of our body, the antibodies, white blood cells fight against the harmful germs by which we got infected. Sometimes our immune system got weaken for overwhelming increase of germs. That time we need the Antibiotics to stop them, so we can get back to normal.
But you should know Antibiotics only work in bacterial infection. In viral infections they do not work like cold, cough, fever.
Antibiotics can’t differ between harmful bacteria & helpful bacteria in our body. So with harmful bacterias they also kill the good bacterias.
In critical conditions when our immune system is not enough, we need antibiotics, but the less use how much we can, will keep us healthy for long life.