In order to locate hydrogen dissolved in metals a nuclear reaction1H(11B, α)αα was applied to a channelling method. As an example of this application the results of the following two experiments were briefly reported. (1) The lattice location of H in V was investigated under a <001> compressive stress of 7 kg/mm2below the elastic limit. The configuration of hydrogen is extremely sensitive to compressive stress and changes from a tetrahedral (T) site to a diplaced-Tor 4Tconfiguration. On release of this stress the hydrogen atoms returned toT-sites. (2) To elucidate the mechanism of the enhancement of the terminal solubility for hydrogen (TSH) in Nb on alloying with undersized Mo atoms, the state of hydrogen was studied in Nb-based Nb-Mo dilute alloys. It was demonstrated that H atoms are trapped by Mo atoms and located at sites displaced fromT-sites by about 0.6 Å. This result supports the trapping model for the enhancement of the TSH in the region of low Mo concentration.