Antibiotics: What They Are, How They Work, and How to Use Them Safely

Antibiotics are medicines that kill bacteria or stop them from growing. They’ve saved countless lives since the 1940s, but they only work on bacterial infections—not viruses like colds or flu. Knowing the basics helps you and your doctor decide when an antibiotic is the right move.

Common Types and When They're Needed

There are many classes of antibiotics, each targeting different bacteria. Penicillins (like amoxicillin) are often first‑line for ear infections, strep throat, and some skin infections. Cephalosporins (such as cefalexin) cover a broader range and are used for urinary tract infections or pneumonia. Macrolides (like azithromycin) work well for people allergic to penicillin and are common for chest infections. Fluoroquinolones (ciprofloxacin, levofloxacin) are powerful but reserved for more serious infections because of higher side‑effect risk.

Doctors choose an antibiotic based on the suspected bacteria, where the infection is, and patient factors like allergies or kidney function. If you get a prescription, it usually means the doctor thinks a bacterial cause is likely. Always ask why a specific drug was chosen—understanding the reason helps you stick to the plan.

Risks, Resistance, and How to Protect Yourself

Antibiotics aren’t harmless. Common side effects include upset stomach, diarrhea, and occasional yeast infections. Rarely, they can cause allergic reactions or affect your heart rhythm. More worrying is antibiotic resistance: when bacteria learn to survive the drug, making future infections harder to treat. Overusing or stopping early fuels this problem.

To keep resistance low, take the full prescribed course—even if you feel better after a couple of days. Never share pills with friends or family, and don’t keep leftovers for “just in case.” If you’re unsure about a symptom, ask your doctor whether a test can confirm a bacterial infection before starting antibiotics.

Sometimes, non‑antibiotic approaches work just as well. For many sore throats, rest, fluids, and pain relievers manage symptoms while the body fights a viral cause. Probiotics can help restore gut bacteria after a course, reducing diarrhea risk. Talk to your pharmacist about supportive measures that fit your situation.

Practical tips for safe use: fill the prescription at a reputable pharmacy, double‑check the dosage schedule, and set reminders so you don’t miss doses. Store pills as directed—some need refrigeration, others stay at room temperature. If side effects feel severe or you notice a rash, call your doctor right away.

Antibiotics are powerful tools when used correctly. By knowing what they do, when they’re needed, and how to avoid misuse, you protect your health and help keep these drugs effective for everyone.