We investigated the influence of Fe3+-NTA on H226b cell growth, degeneration and p53 point mutations, as well as evaluating the influence of low-dose X-ray irradiation. In the result, growth of H226b cells was unsatisfactory when cultured in a higher concentration of Fe3+-NTA (above 6μg/ml) . In contrast, growth of H226b cells was satisfactory when cultured in a Fe3+-NTA concentration of 2μg/ml. In addition, growth of H226b cells cultured in a Fe3+-NTA concentration of 4μg/ml was accelerated by irradiating with 0.25 Gy X-ray. Therefore, it was found that cell growth was synergistically accelerated when H226b cells were supplemented with a low concentration of Fe3+-NTA, which produced small amounts of active oxygen, and irradiated with low-dose X-ray. It was also found that the release of LDH in the medium was inhibited by irradiating with 0.25 Gy X-ray when the culture medium was not supplemented with Fe3+-NTA. Moreover, it was confirmed that the point mutation of the p53 gene was induced along with transformation of H226b cells to H226br cells. Therefore, using this phenomenon, the presence or absence of a p53 point mutation was evaluated. When the human p53 gene exon 7 was used as the primer, a p53 point mutation was not detected. Therefore, it was confirmed that H226b cells did not transform to H226br cells.