Translocation, distribution, and metabolism of 14C-carboxy-labeled dicamba (3,6-dichloro-o-anisic acid) in western bracken [Pteridium aquilinum (L.) Kuhn var. pubescens Underw.] were determined in field and greenhouse trials by liquid scintillation radioassays, autoradiographs, and paper chromatography. Absorption and translocation of 14C readily occurred from 14C-labeled dicamba applied to frond buds, pinnae of new leaves, and rhizome tissue. The translocated 14C tended to accumulate in opened fronds or if fronds had not emerged, in frond buds and rhizome apices. Dicamba applied to living tissue of a quasi-dormant rhizome in the field in spring was translocated to rhizome apices and metabolized to 5-hydroxy-3,6-dichloro-o-anisic acid and 3,6-dichlorogentisic acid 10 days after application.