It is intended to provide a skin protecting composition which can effectively prevent the invasion of infective bacteria such as Pseudomonas aeruginosa, Bacillus subtilis, anthrax, Escherichia coli, Staphylococcus aureus, MRSA, etc. and viruses such as influenza viruses into the body via mucosae of eye, nose, throat, ear, anus, pubes, etc. and, at the same time, inhibit the proliferation thereof;a skin protecting composition which can effectively prevent hospital acquired infection, etc. by drug-resistant strains; a preventive and/or therapeutic composition for bacterial or viral infection including hospital acquired infection; an aseptic; and a filter apparatus which can effectively prevent the invasion of infective bacteria and viruses and inhibit the proliferation thereof. A skin protecting composition, a skin protecting composition capable of effectively preventing hospital acquired infection, etc. by drug-resistant strains; a preventive and/or therapeutic composition for bacterial or viral infection including hospital acquired infection; an aseptic; and a filter apparatus capable of effectively preventing the invasion of infective bacteria and viruses; each characterized by containing a bamboo extract optionally together with an organic acid as the active ingredients.