Abstract: Objective: To investigate the potential effects of realgar on the glioma cells both in vitro and in vivo, and evaluate its role as a novel agent against human glioma. Methods: The 9 L glioma cells were cultured in suitable medium, cell proliferation inhibitory assay was employed to observe the reaction of these cells, including the morphological changes and cytotoxicity by realgar suspension at a certain concentration; local injection or oral administration or both of them were applied on the established subcutaneous 9 L glioma animal models and the corresponding reaction was observed. Results: Realgar showed strong inhibitory effects on the 9 L glioma cells in vitro. According to the trypan blue coloration and cell counting, the suppression ratio of the cells on 4 h, 12 h and 24 h was 40%, 78% and 99% respectively; in the animal model experiment, strong antitumor effects were also observed. In the local injection group, about 75% of the tumours disappeared in less than 3 weeks after injection， and about 8.3% of the tumours relapsed in 3 months. Conclusion: Realgar has strong antitumor effects both in vitro and in vivo,and it is a potential antiglioma agent.

Key words: Realgar, Arsenicals, Glioma, 9 L Cell line, Rats