Goldenseal is a small perennial plant that grows to a height of 6 to 20 inches. Native to eastern North America, goldenseal is found in moist woodlands and meadows. The plant has a hairy, purple stem that grows from a small, twisted rhizome, which is usually less than 2 inches long. The top of the stem has three to five leaves, which are up to 12 inches across and are deeply divided into five or seven lobes. These pointed lobes have finely toothed edges and are covered with soft down. Flowering in May, goldenseal has a single, 1/2 inch diameter blossom with no petals. It has numerous stamens and three greenish-white sepals, which resemble petals. The sepals fall off when the flower opens. Goldenseal bears an inedible, red fruit which resembles a raspberry. The dried rhizome of the plant is used for health purposes.
The chief active components in goldenseal are the alkaloid compounds berberine, hydrastine, canadine, and berberastine. Berberine is the most extensively researched of the four compounds, and is believed to be the most biologically active.
The recommended dosage for goldenseal supplements depends upon their berberine content. The following doses can be taken three times daily: dried root (as an infusion or tea), 2-4 grams; tincture (1:5), 6-12 milliliters; fluid extract (1:1), 2-4 milliliters; powdered dry extract (8-12 percent alkaloid content), 250-500 mg. Goldenseal has no known toxicity within this dosage range.