Illness refers to a state of poor health that can affect the body or mind. It can be caused by various factors, including infections, genetic conditions, or environmental influences. Common examples of illnesses include flu, diabetes, and depression. Symptoms may vary widely, ranging from mild discomfort to severe pain. Treatment for illness often involves medical intervention, such as medication or therapy, and lifestyle changes. Preventive measures, like vaccinations and healthy habits, can help reduce the risk of certain illnesses. Understanding the nature of an illness is essential for effective management and recovery.