6. Routine consumption of more than 2 units of caffeine per day or subjects who experience caffeine withdrawal headaches. (1 caffeine unit is contained in the following items: one 6oz (180mL) cup of coffee, two 12oz (360mL) cans of cola, one 12oz cup of tea, three 1oz (85g) chocolate bars. Decaffeinated coffee, tea, or cola are not considered to contain caffeine)