Certain operative endoscopic and indirectly monitored procedures require liquids for cavity distention or x-ray contrast media. Transmission of neodymium:yttrium-aluminum-garnet (Nd:YAG) at wavelengths of 1.06 Lim and 1.32 μm through various fluids was investigated. For most of the water-diluted solutions studied, the absorption coefficient is similar to that of water for both wavelengths. For the Nd:YAG 1.32 μm laser beam, there is almost no absorption in Lipiodol and about half of the absorption in Urografin and Endografin as in water. Our data confirm that it is possible to apply these specific wavelength lasers also for invasive procedures guided by x-ray through contrast media, where the lower absorption coefficient offers an advantage. The solution to be used, if required, depends on the medical indication.