Always take the entire course of antibiotics as directed by your doctor. Even though you may feel better before your medicine is entirely gone, follow through and take the entire course. This is important for your healing. If an antibiotic is stopped in mid-course, germs (bacteria) may be partially treated and not completely killed. Bacteria may then become resistant to that antibiotic. Overuse of antibiotics has led to some bacteria changing their form or structure (mutating) and becoming resistant to some antibiotics, which may then not work when really needed. For example, meticillin-resistant Staphylococcus aureus (MRSA) is a bacterium that has become resistant to many different antibiotics and is difficult to treat