What are the symptoms of overdosing on green tea?

Caffeine: Green tea contains caffeine, so the symptoms of overdosing may be similar to overdosing on any caffeinated beverages -anxiety, heart palpitations, insomnia. Also, caffeine is a diuretic, so overdosing can cause frequent urination and dehydration.

Green Tea O/D: If you drink five or more cups of caffeinated green tea it can cause an increase in blood pressure for some people, as well as gastrointestinal upset (nausea or vomiting), irritability or insomnia. It can interact with some medications. It could aggravate anxiety disorders, diabetes ; some bleeding disorders.