Goldenseal is commonly praised for its ability to soothe the mucus membranes of the body, relieve inflammation, and eliminate any unwanted pathogens or microbes. For the treatment of giardiasis, this herb is quite popular, as it can flush out the gut and intestinal membranes, making it difficult for the giardiasis parasite to latch on and multiply. The active ingredient in goldenseal is berberine, which is a strong anti-parasitic compound that can boost your immune system and make quick work of the giardiasis infection.