You are in Medical Library . Large amounts of histamine are released in response to an injury or in conjunction with an antigen-antibody reaction, such as an allergic reaction.
Histamine also dilates small blood vessels and increases their permeability.
Histamine is a potent stimulant of acid secretion in the stomach. Antihistamines are better at preventing reactions than treating them and are useful if an allergic reaction, such as hay fever, is expected. Inc. All Rights Reserved. From The World Book Rush-Presbyterian St. Luke's Medical Center Medical Encyclopedia . All rights reserved.