An antibiotic is a type of medicine that helps fight infections caused by bacteria. They work by either killing the bacteria or stopping them from growing. Common examples of antibiotics include penicillin and amoxicillin. Doctors prescribe antibiotics to treat various illnesses, such as strep throat or urinary tract infections. It's important to use antibiotics responsibly. Taking them when they are not needed can lead to antibiotic resistance, where bacteria evolve and become harder to treat. This is why it's crucial to follow a doctor's advice and complete the full course of antibiotics, even if you start feeling better before finishing the medication.