It’s best not to drink green tea on an empty stomach, as the tannins it contains can increase the acid in your stomach. This can lead to tummy aches for those with sensitive stomachs. For those with peptic ulcers or acid reflux, drinking green tea on an empty stomach may aggravate the condition.
It’s suggested that you have a little something to eat before you drink your green tea first thing in the morning, or at the least, drink it at a weaker strength.
Note, there are certain medications green tea may interfere with, so if you have a health condition, check with your doctor about whether it is safe for you to drink green tea.