<p>A barium salt of the S-enantiomer of omeprazole which is (S)-5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)-methyl]sulfinyl]-1H-benzimidazole is provided. Further, processes for preparing the barium salt, pharmaceutical compositions comprising the salt and a method of treatment or prevention of gastrointestinal ulcers comprising administration of the salt are provided.</p>
