Just wanted to throw out there that I think dandelion root as a tea doesn't work as well for stimulating bile production. I drank the tea rather religously for a few weeks not really noticing any change, and on a whim(after hearing about my little sister was doing so well on the supplement that I sent her because she's 15 and tea is "not cool"), I broke open an unused tea bag and swallowed the contents(like crumbley dirt yum lol) and it worked just as well as coptis! I laid down and felt my upper abdomen rumbling almost happily before bed.
But both my dad and my sister are reporting their skin(dad has chronic Acne and little sis has mild teenage acne) is doing better, and my dad says his chronic gas is much better as well. All from a $10 bottle of dandelion root supplements. I only thought of how ingesting the root directly might work better after reading how milk thistle's liver detoxing properties don't work unless its in ticture form.