A light source for medicine, with which visibility of blood vessels in the skin can be promoted when an injection is performed on the human body, is provided. The light source for medicine of the present invention has a P3 to P2 ratio (P3/P2) of 19% or less, wherein P3 is the maximum intensity of the emission spectrum within a wavelength region from 520 nm to 580 nm, and P2 is the maximum intensity of the emission spectrum within a wavelength region from 600 nm to 780 nm.