Whether an allergy or intolerance, like a doctor said, some people are extremely sensitive to it. Also, the coffee in the US causes problems, but where I live now in Costa Rica, the coffee is grown here is pure, and doesn't. Even decaf from the US affects me. I decided to give up the coffee here too because although 1 cup of coffee does not affect my heart, I have a tremor in my right hand, and am testing to see whether abstinance will,get rid of it. but the bottom line is to eliminate it. And I REALLY love coffee and dark chocolate.