This video briefs us about the drugs used in allergies like histamines and their interaction with receptors to produce a positive effect and treat allergic reaction occurring from tissue damage primarily. 0:11 Introduction 0:15 Histamine 0:54 Allergic reactions 1:48 Tissue injury 1:50 Drugs and foreign chemicals 2:07 Histamine receptor effects 3:54 H-1 receptor blockers (Antihistamines) 7:21 H-2 receptor blockers 7: 25 Conclusion