I'm not on any medications, and I've never been able to handle tea in the morning. Green, black, iced, hot, matcha. It always makes me feel nauseated unless I've eaten breakfast first. I always drink black coffee though, without problems.

I am similar. Green tea always makes me feel nauseous on an empty stomach. Tea with milk is normally ok.

That's why the Brits are having it ;-)

This is due to the high concentration of tannin in the tea. It causes stomach problems if you dont have protein in your belly already.