Histamine Dihydrochloride. Histamine dihydrochloride (pronounced hiss-ta-mean dye-hide-row-klor-ride) is a form of histamine—a compound that does many things in the body. For example, histamine is released by immune system cells during allergy season and is the reason for runny noses and watery eyes.Some people may take antihistamines, which block the action of histamine. Tip. In other products, histamine dihydrochloride may be called histaminum hydrochloricum.On the product website, they say histamine dihydrochloride is an “external analgesic.” An analgesic is something that relieves pain.he Australian Dream does work, and from this review, I am thinking the blood supply is probably the reason it works for me. I think it is like any other drug, it works for certain things and not others. I do not want to get steroid shots in my back, and I am thankful this helps.