The present invention relates to a pharmaceutical composition for preventing or treating voiding dysfunction and a health functional food for preventing or improving of voiding dysfunction, comprising extract of Piper Longum L. as an active ingredient. The extract of Piper Longum L. according to the present invention is not only harmless, but also has outstanding effects of preventing, treating and improving voiding dysfunction by being involved in various mechanisms related to voiding dysfunction simultaneously so that it may increase a micturition interval, decrease a micturition pressure, increase a bladder capacity, inhibit detrusor contraction and induce relaxation of detrusor.
