  We discuss constraints on three flavor neutrino mixings from the accelerator
and reactor experiments, the Kamiokande multi-GeV data, and the solar neutrino
observations. The LSND result is excluded at 90\%CL by the constraints imposed
by all the data of reactor and accelerator experiments and the Kamiokande
multi-GeV data if the mass scale required for the solution to the solar
neutrino problem is hierarchically small. The region of a set of the effective
two-flavor mixing parameters ($\Delta m^2$, $\sin^22\theta$) is given for the
channel $\nu_\mu\rightarrow\nu_e$ which is allowed at 90\%CL by the multi-GeV
Kamiokande data alone.
