Polymorph 1 of 4-Ä2-Ä1-(2-ethoxyethyl)-1H-benzidimazole-2-ylÜ-1-piperidinylÜ ethylÜ- alpha alpha -dimethyl-benzenoacetic acid of formula (I) is described, procedures for its preparation, pharmaceutical formulae containing polymorph 1 and the use of polymorph 1 to treat allergic reactions and pathological processes mediated by histamine in mammals such as man. <;CHEM>;