Provided is a bioabsorbable peptide tissue occlusive agent applicable to large mammals including humans, which is an artificially synthesized peptide tissue occlusive agent free from infectious concerns such as viruses. A tissue occlusive agent comprising a peptide, wherein the peptide is an amphiphilic peptide having hydrophilic amino acids and hydrophobic amino acids alternately linked and having amino acid residues of 8 to 200, physiological pH and / or Alternatively, a tissue occluding agent that is a self-assembling peptide that exhibits a β structure in an aqueous solution in the presence of a cation.ヒトを含む大型哺乳動物に適用可能な生体吸収性のペプチド組織閉塞剤であって、ウイルスなどの感染性の懸念のない人工合成によるペプチド組織閉塞剤の提供。ペプチドを含有する組織閉塞剤であって、該ペプチドが、親水性アミノ酸と疎水性アミノ酸とが交互に結合し、アミノ酸残基８～２００を有する両親媒性のペプチドであり、生理的ｐＨおよび／または陽イオンの存在下、水溶液中でβ構造を示す自己組織化ペプチドである組織閉塞剤。
