To provide a pharmaceutical composition which is useful for improving cerebrospinal fluid hypovolemia (intracranial hypotension syndrome).

Either glucosamines or glycosaminoglycans (such as chondroitin, chondroitin sulfate or the salt thereof) may be incorporated into collagen composing gelatin or into peptide or amino acid composing collagen, the regeneration of meninx and the peripheral tissue of meninx are promoted by a simple substance or combined composition, and the functions of meninx and the peripheral tissue of meninx are normalized to prevent the leakage of cerebrospinal fluid. Thus, cerebrospinal fluid hypovolemia (intracranial hypotension syndrome) is improved and prevented.