There have been spotty reports that kombucha consumption can indeed be dangerous.
There is little evidence to back this up, but according to Dr. Michele Berman:
[t]he greatest danger from kombucha seems to arise in “home brew” versions that have become contaminated because of improper preparation and/or when kombucha interacts with alcohol or prescription drugs.
People should be careful when consuming kombucha, especially if it’s made at home. And if you take prescriptions, it’s good to check with your doctor to ensure that there won’t be any adverse reactions (it sounds like some may be due to the small amount of alcohol content interfering with certain meds).
By and large, however, kombucha is extremely safe to drink and the entire beverage should not be tarred just because of a few instances of misuse.
