1. A chemical compound released by cells in the body during allergic reactions and immune responses, causing inflammation, itching, and other symptoms.
Usage: biochemistry; medicine

Examples

• When you have an allergic reaction, your body releases histamine, which causes itching and swelling.
• Antihistamine medications work by blocking the effects of histamine in the body.
• Histamine levels increase during an asthma attack, making breathing more difficult.
• The doctor explained that histamine is responsible for the hives that appeared on my skin.
• Some foods naturally contain high levels of histamine and can trigger reactions in sensitive people.