That has not been my experience. My liver was so congested that my skin turned yellow, I developed ascites, my side was hurting, my stomach swelled up and I couldn't bear to wear anything around my waist. No pants, just dresses. I took oogles of herbs, way more than the recommended dose of many (not bloodroot). And I have steadily improved. Can you take too much of anything? Sure.
You can overdose on water and drown yourself too. The reason most people think herbs don't work is because they are afraid to take enough to help themselves. Should you start with a lower than recommended dose and build up? Yes. Should you carefully select the particular herbs that are known to address your symptoms? Yes, so that you don't confuse your body with a bunch of chemicals it doesn't need.