This large herbaceous plant has a stem that can reach between 60 and 120 cm in height and is covered by fine, short, soft hairs. The flowers of the common boneset are small and white, gathered in flat corymbs.
The leaves measure from 10 to 15 cm in height, sometimes up to 25 cm in well-developed specimens. They are opposite and perfoliate: the stem passes through the base of the leaves, whence the species name “perfoliatum.”
The flowers produce small seeds called achenes (dry fruit containing just one seed, not open at maturity). Seeds range in color from light brown to dark brown. They have pappi, tufts of fine, whitish hairs.