The kinetics and mechanism controlling the aqueous dissolution from the (110) plane of salicylic acid (SA) in the presence of the solution phase ionic additives sodium chloride, lithium chloride, and magnesium chloride; the organic additives I-propanol and 2-propanol; and the surfactant sodium dodecyl sulfate (SDS) have been investigated using a hydrodynamic atomic force microscope flow cell. Topographical images reveal that the surface dissolves via the retreat of macrosteps across the surface in the presence of the ionic additives at low concentrations (0.1 M). The rate of step retreat is dependent on the step height and the presence of hillocks on steps and planes. As the concentration of NaCl and LiCl is increased to ca. 1.0 M the height of the macrosteps decreases. For MgCl2, in contrast, dissolution at high concentrations is inhibited, and after a transient dissolution, the surface features then remain intact. In the presence of the aqueous organic additives and the surfactant, the surface morphology differs from that after exposure to the ionic additives in that the (I 10) face is less rough with considerably smaller macrosteps. The flow pattern in the hydrodynamic AFM flow cell is well established, allowing the deduction of dissolution rate. The dissolution flux has been studied as a function of flow rate and quantitatively interpreted using a model combining dissolution with the possibility of partial reprecipitation, the latter having a first order dependence on the surface concentration [SA](0): J = k(f) - k(b) [SA](0). In the modeling, the ratio k(f)/k(b) is constrained to be equal to the measured solubility of SA in the medium concerned. This simple equation was found to give a good fit to the kinetic data obtained in the presence of the ionic additives only. However, satisfactory parametrization of the data was possible if k(f) and k(b) were optimized independently of the solubility constraint. The parameters for k(f) are found to be 1.7 x 10(-8), 1.5 x 10(-8), and 8.9 x 10(-9) Mol cm(-2) s(-1) for dissolution in 0. 1 M, 0.5 M, and I M NaCl or LiCl, and 1.5 x 10(-8) for dissolution in 0.1 M MgCl2. For 1 M MgCl2, the rate was too small to measure. For the organic additives and surfactant, the rate constants are different for each additive but independent of additive concentration. Values for k(f) and k(b) are found to be 1.4 x 10(-8) mol cm(-2) s(-1) and 2.0 x 10(-3) cm s(-1) for dissolution in 0.5 and 1.0 M 1-propanol; 1.8 x 10(-8) Mol cm(-2) s(-1) and 2.0 x 10(-3) cm s(-1) in 0.5 and 1.0 M 2-propanol and 2.2 x 10(-8) Mol cm(-2) s(-1) and 3.0 x 10(-3) cm s(-1) in 0. 126 mM, 0.252 mM, 1.26 mM, and 2.52 mM SDS.