Reaction of H.-atoms produced photolyticaly in acid glasses with myo-inositol initially results in the formation of three different radical intermediates, two of which give rise to discernable hyperfine interactions in electron spin-resonance spectra whereas one is a non-specific singlet. The two former species correspond to loss of H. from all carbon-positions of the polyalcohol. Both intermediates transform into the same secondary radical upon thermal annealing by water elimination.