My issue wasn't the enzyme, it made no difference. The histamine blockers did nothing also. It seems that as histamines are important for cellular permeability and deliver immune factors to where there is inflammation / infection, they have their job to do. My histamines didn't quiet down until I helped with the detox reaction--CEs, and not only low-histamine foods but foods that inflame me or pull more from tissues. And then the body seems to do heavy-duty detox in waves so there are days when histamines become elevated despite best efforts.