Diphenhydramine is an antihistamine, antiemetic and antispasmodic. The use of this medicine is recommended for the treatment of allergic diseases such as hay fever, angioedema, contact dermatitis, atopic dermatitis, allergic rhinitis, pruritus, gastrointestinal allergies, physical allergies, allergic transfusion reactions, reactions to infection of contrast media, and reactions to therapeutic preparations. It is also recommended for postoperative nausea and vomiting, motion sickness and emotionally disturbed children. When this medicine is used for motion sickness, it has to be administered 30 minutes before the event that may cause the motion sickness and preferably 1 or 2 hours before.