Highly effective optical power-limiting and optical-stabilization performances have been achieved in a new type of two-photon absorbing medium. That is a liquid-dye salt system, trans-4-[p-(N,N-dimethoxyethylamino)styryl]-N-3,6,9-trioxadecylpyridinium tetrafluoroborate (abbreviated as ASDPT), which features an unusually high molar concentration (-1 M) of two-photon absorbing chromophores and the capability of withstanding a higher pulsed laser power and energy. The nonlinear transmission property and output-input characteristics were studied based on a 1-cm-long liquid-dye salt sample by use of nanosecond 1064-nm laser pulses with a repetition rate variable from 1 to 10 Hz. A superior optical-stabilization behavior of the studied material was demonstrated; the relative fluctuation of the nanosecond laser pulses can be reduced by more than two times simply by passing them through this highly concentrated nonlinear absorbing medium.