A brief review is given of the mechanisms responsible for a number of well-known electro-optical and magneto-optical effects, and also the spatial dispersion effects in isotropic (under rotations) liquids. Theoretical estimates and typical experimental values of constants are given. The existence and detection of a number of new electro-optical, magneto-optical, and magneto-electro-optical effects in transparent isotropic liquids are examined. It is indicated which effects are forbidden under left-right reversal symmetry and time-inversion symmetry (no relaxation processes). The mechanisms responsible for many of the effects are considered and the values of the corresponding constants are reproduced. Despite the fact that these constants are small, the effects appear to be measurable through the application of the synchronous detection technique using modulated external electric and magnetic fields.