This invention is directed towards a method of using visible light at wavelengths of at least 500 nm and above in combination with a sensitizer having a flavin moiety to reduce any pathogens that may be contained in blood and blood components. By exposing the blood and blood components to light of 500 nm and higher, only the sensitizer that is bound to nucleic acids of the pathogens will be activated, thus destroying the sensitizer-pathogenic nucleic acid complex. Because unbound sensitizer is not activated at this wavelength, damage to blood and blood components caused by photolysis of unbound sensitizer may be avoided.