Eleven autopsy specimens of healthy human abdominal aorta were irradiated under normal saline at room temperature (21.5±1.5°C) using an excimer laser (308 nm, 40 Hz, 115 ns, 57 mJ/mm2, 900-μm fused silica fiber). After irradiation, transmission spectra from untreated areas and from the damage zone next to the ablation area were obtained by microspectrophotometry (250- to 800-nm spectral range, 25-μm cryosections, 6.3-μm-diam measured area). The optical density (OD) of the damage zone was significantly increased over that of untreated areas in the near ultraviolet and parts of the visible spectral range. The OD of the irradiated tissue was higher, up to a factor of 2.4 for intima, a factor of 3.7 for media, and a factor of 2.3 for adventitia. At 308 nm, OD increased from 0.094±0.019 to 0.237±0.041 for intima (p<0.001), from 0.165±0.053 to 0.501±0.034 for media (p<0.001), and from 0.119±0.017 to 0.276±0.026 for adventitia (p<0.001). We show that excimer laser irradiation using a high repetition rate in combination with a high energy density changes significantly the optical properties of a human vessel wall.