This biennial or short-lived perennial plant is 3-6' tall, branching occasionally. The stout stems are terete, glabrous, and sometimes glaucous; they are pale green, pink, or reddish purple, often with prominent longitudinal veins. The lower portion of the central stem is hollow. The compound leaves are odd-pinnate or doubly odd-pinnate; they alternate along the stems. The lower compound leaves are up to 1½' long and ¾' across; the upper compound leaves are much smaller. Each division of a compound leaf typically has 3-7 leaflets. The bases of petioles are partially enclosed by their sheaths; otherwise they are similar to the stems in appearance, although more slender. The glabrous leaflets are 1½-4" long and ½-1¼" across; they are oblong-elliptic with wedge-shaped bottoms, tapered tips, and dentate margins. Sometimes the leaflets fold upward along the length of their central veins. Leaflet venation is pinnate. The lateral veins of leaflets extend to the notches between the teeth, rather than to their tips, along the leaflet margins. The upper stems occasionally produce compound umbels of small white flowers. These compound umbels are up to 6" across and consist of 10-20 umbellets. Individual umbels are dome-shaped on top, rather than flat. Individual umbellets have about 12-15 flowers that are clustered together. Each flower is about 1/8" across, consisting of 5 white petals, an insignificant calyx, 5 white stamens, and a divided style. The tiny petals are constricted at their bases, and they have notched tips. The blooming period occurs during mid-summer, lasting about 1 month. The flowers have a slight fragrance that is sometimes detectable. Afterwards, each flower is replaced by a small angular fruit containing a pair of seeds. The root system consists of several fleshy roots at the base of the plant; they are ovoid or oblongoid in shape. These fleshy roots are exceptionally poisonous; the stems and foliage are somewhat less poisonous. This plant spreads by reseeding itself into neighboring areas.