What are the situations in which tea becomes harmful?

Despite the benefits and less danger of tea compared to coffee, it becomes harmful in these cases:

1- If it is drunk immediately after eating: it causes constipation and prevents iron absorption

2- If it is boiled a lot, it turns into a dark brown color: which causes disturbances in the heart muscle

3- If it is consumed in excess and in abundance: it causes stomach and duodenal ulcers

4- If it is drunk on an empty stomach: it prevents the release of digestive juices and causes laziness in the digestive system

5- Patients with kidney stones and patients with stomach ulcers: it causes aggravation and worsening of their health condition