Pregnant women should limit themselves to no more than three cups of tea a day since excess caffeine can cause things like premature birth and low birth weight.
For people with iron deficiency, drinking tea can interfere with how your body takes in iron.
You should not drink oolong tea with other stimulants such as amphetamines or ephedrine. That could cause serious heart problems.
Avoid oolong tea if you take blood-thinning medications or if you use herbs or supplements that slow down blood clotting,like