A nonuniform magnetic field induces an inhomogeneous ferroparticle distribution in a magnetic fluid (MF). As a consequence the magnetic field influences MF flows. In particular, we consider an oscillatory pipe flow in a stationary nonuniform magnetic field subject to the quasielastic magnetic force. Concentration inhomogeneities can be formed from both single particles and many‐particle drops, which appear as a result of the field‐induced MF phase separation. Kinematic considerations show that only the drops contribute to the magnetic force. Our theory is in good agreement with recent experimental results. ©1995 American Institute of Physics.