long-term use of anti-biotics produces "super bugs," germs (using the generic, non-scientific term) that are resistant, or immune, to the antibiotic. superbugs are beginning to render many antibiotics useless. it's darwinian. the antibiotic ia effective against 99.9% of the germs and your body recovers from the infectiuon. but the .1% are still there and grow becausse the antibiotic cannot touch them. some researchers are preaching doom and gloom because they are predicting that we may revert to a pre-antibiotic period of medicine.