Superoxide and hypochlorite radicals are involved in both normal and pathological processes in the human body. Excessive production of any of them may result in malignization of healthy cells. The ideal chemotherapeutic must exhibit prooxidant action in the tumor and antioxidant behavior in healthy tissues. Lanthanum (III) salts have been investigated for their antibacterial and antitumor activity. 5-aminoorotic acid (HAOA) has antioxidant properties. In this work the interaction of HAOA and its Lanthanum (III) complex (LaAOA) with with superoxide and hypochlorite radicals was evaluated in vitro by way of two superoxide-generating and one hypochlorite-generating systems at normal physiological pH. Luminol-dependent chemiluminescence (LDCL) and UV spectroscopy were used to estimate the radicals scavenging properties of the investigated compounds. The ability of both compounds to exchange electrons and to donate hydrogen was estimated by the utilization of two models of stable free radicals. Both HAOA and LaAOA were capable of participating in electron transfer and hydrogen donation, therefore they behave like promising antioxidants. The latter was proven by monitoring their interactions with superoxide (potassium superoxide and xanthine/xanthine oxidase generated) and hypochlorite (NaOCl generated) radicals in vitro. The complex LaAOA behaved as a better antioxidant than 5-aminoorotic acid itself. This suggested that these compounds would protect healthy tissues from oxidative damage. The antioxidant behavior of LaAOA and HAOA was in agreement with the 3D structure and UV-spectra of the compounds. It was suggested that LaAOA might be a promising anticancer agent with antioxidant properties.