My father is hyper-sensitive to caffeine, and I am quite sensitive as well. More than a cup of coffee and I get the shakes.

My father on the other hand will get blurred vision and an irregular heart beat. He is other wise extremely healthy and in good physical shape.

I started drinking this tea called Yerba Mate, my highschool spanish teacher introduced me too it. I spent some time living in Uruguay where it is something of a national beverage.

It has the caffeine to get you up and going, but something about it doesn't effect people the same as coffee. It takes an awful lot of it for the effects to impact me negatively and at that it is nothing like coffee.

My father has been drinking probably about 2 liters of it per day since I introduced it to him. He has had no ill effects.

Any way you should check it out. It is supposed to have a lot of good minerals, vitamins, and antioxidants too. But, for me it's just my hot beverage of choice. It wakes me up and I have grown to thoroughly enjoy the taste.