What are allergies?

Allergies are one of the most common chronic conditions in the world. Some 40 million to 50 million people in the United States have them.

What is histamine?

Histamine is an important chemical that has a role in a number of different bodily processes. It stimulates gastric acid secretion, plays a role in inflammation, dilates blood vessels, affects muscle contractions in the intestines and lungs and affects your heart rate.