The Borexino liquid scintillator detector, originally designed for solar neutrino study, is also a sensitive instrument in searching for rare events in the energy range of about 1 MeV. The recent results include the search for nonstandard neutrino interactions, as well as limits on diffuse neutrino fluxes from Supernovae, solar flare neutrinos and solar antineutrinos, expected as a combined effect of spin-flavour neutrino precession in the magnetic field of the Sun and neutrino oscillations.

The best limit on the solar flare neutrino fluence in the energy range below 3 MeV was obtained and the first experimental limit on the diffuse neutrino flux from Supernovae in the range from 1.8 to 8 MeV was defined. The limits on parameters of nonstandard neutrino interactions and the solar antineutrino flux are comparable to the results of other experiments.