B-cell acute lymphoblastic leukemia (B-ALL) is a type of cancer that affects the blood and bone marrow. It occurs when the body produces an excessive number of immature white blood cells called B-lymphocytes. These abnormal cells crowd out healthy blood cells, leading to symptoms such as fatigue, frequent infections, and easy bruising or bleeding. B-ALL is most common in children but can also occur in adults. Treatment typically involves chemotherapy, which aims to kill the cancerous cells and restore normal blood cell production. Early diagnosis and intervention are crucial for improving outcomes in patients with this condition.