New polymorphic forms of olanzapine

Disclosed is a method for producing a olanzapine polymorph comprising: dissolving a starting olanzapine polymorph in an aqueous acid solution, wherein the aqueous acid solution comprises an acid selected from the group of organic or inorganic acids, and cases of another olanzapine polymorph by neutralization; wherein the neutralization by the addition of an aqueous or alcoholic solution of a base is brought about, and the use of olanzapine polymorph for the preparation of a pharmaceutical composition for treating a condition selected from the group of psychotic states, mild anxiety and gastrointestinal complaints.