Drinking four to six mugs of tea every day is good for keeping you hydrated as much as one litre of water. This idea refutes the claim that regular tea drinking can dehydrate the body as it has caffeine content. Although, a moderate intake is healthy for most of the adults, drinking in excess can have a clear negative side effect that can cause anxiety, headaches, digestive issues, disturbed sleep, etc.
Drinking herbal tea in moderate quantity can be beneficial for your health but an excess intake can be detrimental to your body. For some the limit of 4 cups is sufficient but for some anything lower can be a good idea.