PROBLEM TO BE SOLVED: The present invention provides a novel therapeutic agent for alopecia. The therapeutic agent of the present invention is effective and safe for treating alopecia, especially alopecia areata, androgenetic alopecia of male, androgenetic alopecia of female, female pattern alopecia, postpartum alopecia, seborrheic alopecia, alopecia pityroides, senile alopecia, alopecia caused by chemotherapy drugs or radiation exposure, and is effective for treating patients showing therapy resistance to minoxidil or finasteride. The therapeutic agent of the present invention has no side effect, such as etching, stimulating or feminizing, or contraindication. The therapeutic agent is also useful for the treatment of dandruff and white hair. Additionally, the therapeutic agent of the present invention can retain effectiveness for a long time even if the patient discontinues using it. SOLUTION: The therapeutic agent for alopecia of the present invention comprises C-type natriuretic peptide or B-type natriuretic peptide, derivatives of said NPs, chimeric peptides of said NPs, or derivatives of the chimeric peptides of said NPs as an active ingredient.本發明的課題係提供一種新穎的脫毛症治療劑，其不僅對於脫毛症且特別是對於圓形脫毛症、男性之男性型脫毛症、女性之男性型脫毛症、女性型脫毛症、分娩後脫毛症、脂漏性脫毛症、糠秕性脫毛症(alopecia pityroides)、老年性脫毛症、癌症化學治療劑性脫毛症、輻射暴露所致之脫毛症而言，係有效且安全，對於對敏諾西迪或非那斯特萊有治療抵抗性之對象亦有效，無搔癢感、刺激感、女性化等副作用，無使用禁忌，能抑制頭皮屑，具有白髮治療效果，即便中止使用亦能長期不失去脫毛症治療效果。 本發明之解決手段，係一種脫毛症治療劑，其係以C型排鈉利尿胜肽（CNP）或B型排鈉利尿胜肽（BNP）、這些排鈉利尿胜肽（NP）之衍生物、這些排鈉利尿胜肽（NP）之嵌合肽(chimeric peptide)、或這些NP之嵌合肽之衍生物。
