Autoimmune diseases occur when the body's immune system mistakenly attacks its own healthy cells, thinking they are foreign invaders. This can lead to inflammation and damage in various parts of the body. Common examples of autoimmune diseases include rheumatoid arthritis, lupus, and multiple sclerosis. These conditions can affect anyone, but they are more prevalent in women. Symptoms vary widely, ranging from fatigue and joint pain to skin rashes and digestive issues. Early diagnosis and treatment are crucial for managing symptoms and improving quality of life for those affected by autoimmune diseases.