Histamine block has really been a game changer with my Mast Cell Activation. I started flushing bright red and burning hot on my face, had incredible heartburn, palpitations and tachycardia aswell as chronic fatigue. I could eat 2 foods and that was it!!! 2 safe foods that didnt cause a reaction. Until i found Histamine Block. I can now eat much more! I dont flush AT ALL when i have it. As soon as i run out i have terrible flushing again. My reactions in my throat (mild anaphylaxis) nearly vanished. This stuff works so well for me. Highly recommend giving it a go if you have Mast Cell Activation or Histamine Intolerance.