Indole, α-naphthol, pyrogallol, coumarin, and salicylic acid interacted with the auxins, IAA (indol-3yl-acetic acid), NAA (naphth-lyl-acetic acid), and 2, 4-D (2, 4-dichlorophenoxyacetic acid), supplied to the basal ends of cuttings of Phaseolus vulgaris (L.), giving synergistic or antagonistic effects in root formation. Antagonism in rooting was always associated with increased accumulation of radiocarbon from carboxyl-14C-labelled auxins in the tops of the cuttings. Distribution of auxin over a greater length of the cutting was accompanied by a reduction in root formation. The chemicals which synergized auxin-induced root formation did not promote accumulation of radiocarbon of the exogenously applied labelled auxins in the upper parts of the cuttings.