The present invention relates to pharmaceutical compositions of nitrites such as inorganic nitrites, or any pharmaceutically acceptable salts, solvates, or prodrugs thereof, and the medical use of these compositions. The pharmaceutical compositions, which can be formulated for oral administration, can provide immediate release or extended release of the nitrite ion (NO2−). The pharmaceutical compositions of the invention are useful, for example, for modulating brain function, in particular improving mood and/or psychological state, in the treatment of disorders of brain development, and in the treatment and/or reduction of pain.