Antibiyotik, or antibiotics, are medications used to treat infections caused by bacteria. They work by either killing bacteria or inhibiting their growth, helping the body's immune system to fight off the infection. Common examples include penicillin and amoxicillin. It's important to note that antibiyotik are ineffective against viral infections, such as the common cold or influenza. Misuse or overuse of antibiyotik can lead to antibiotic resistance, making it harder to treat bacterial infections in the future. Proper use and adherence to prescribed courses are essential for their effectiveness.