It is shown by simulation and expt. that selective pulses designed to invert or excite magnetization over a limited frequency window induce significant phase shifts over a bandwidth much larger than the chosen window. These phase shifts affect all expts. where selective pulses are used after exciting transverse magnetization or generally p-quantum coherence. The phase shifts may be compensated by modifying the phases of the rf pulses during the expts. or in some cases by suitable data transformations. [on SciFinder (R)]