I would like everyone who takes goldenseal to be aware that it is native to the eastern US and is seriously endangered there due to over-harvesting as well has habitat loss. Please look for goldenseal from sustainably-farmed sources (preferably organic). This plant does NOT grow like a weed, but takes about 7 years to reach maturity. It naturally grows in the woods, so it needs to be kept shaded.
According to Wikipedia.org, "There are several berberine-containing plants that can serve as useful alternatives, including Chinese coptis, yellowroot, or Oregon grape root."
Type "goldenseal" into Wikipedia for more information.
Do encourage those who farm it to keep it up, even if you must pay a higher price than for goldenseal someone ripped out of the wilds and didn't bother replacing.