It contains tannin. Tannin or tannic acid curbs thirst and results in less demand for further consumption of tea or coffee. Coffee and tea both temporarily raise the body temperature. A few minutes after drinking coffee, the stimulation of the dopaminergic system causes colder extremities and a simultaneous rise in systemic temperature. Tea has a much milder effect in this regard.
Iced tea seems to be the mildest and safest of caffeinated drinks.
A patient with high fever is harmed by coffee and helped by tea and lemon juice. Herbal tea Just because tea is less harmful than coffee does not imply that herbal tea is good or healthy for anyone. Herbal teas are a variety of different dried vegetable leaves. Because of the variety in strength and quality of chemicals in herbs, the use of herbal teas should be avoided. Catnip, juniper, nutmeg, and hydrangea may be hallucinogenic.