Addiction to alcohol or other drugs (from barbiturates to cocaine) is a physical and emotional dependence on that substance and the effects it produces. It involves a loss of control,...

Acquired immunodeficiency syndrome (AIDS) is a disease that severely weakens the immune system, making the body vulnerable to certain infections or cancers, which usually prove fatal AIDS is caused by...

Asthma makes the airways to the lungs prone to bouts of narrowing, resulting in breathing difficulties. Things that trigger asthma attacks include respiratory infections, substances that cause allergies (pollen, dust...