The potential of nicotinic acid (NiAc), a vitamin B3 compound with antioxidant activity, to protect human albumin against the damage caused by exposure to 254-nm UV-C radiation was investigated. Experiments performed at irradiance levels of 3.5-15 W m^(-2) and application times between 5 and 30 min showed that albumin undergoes rapid dose-dependent aggregation when subjected to irradiation. Addition of 0.2 mM NiAc to the albumin solution resulted in a remarkable reduction of protein damage. Protection provided by NiAc was effective up to radiation doses of about 30 kJ m^(-2), which are significantly higher than those required for complete microbial and viral inactivation.