Post-Exposure Prophylaxis (PEP) is a medical treatment designed to prevent infection after potential exposure to a virus, particularly HIV. It involves taking antiretroviral medications as soon as possible, ideally within 72 hours of exposure, and continuing the treatment for 28 days. PEP is recommended for individuals who may have been exposed to HIV through activities such as unprotected sex, sharing needles, or occupational exposure. It is crucial to seek medical advice promptly to assess the risk and determine if PEP is appropriate for the situation.