As a rule of thumb anything from a plant or fungus contains toxins. Whether it's worth it for you to ingest them is very individual but a good way to approach it is to try a sufficiently long period of perfect carnivore and then follow it by a period when you just add the tea. Compare results then.

This doesn't account for chronic damage (so e.g. if you did this with a high-oxalate food you could get kidney stones later but can't know based on that test) but better than nothing.