Antitumor agents with a combined use of a tublin polymerization inhibitor having an antitumor activity with an antiinflammatory agent. These two active ingredients may be contained in a single preparation. Alternatively, two preparations containing the respective ingredients to be administered separately may be combined with each other. In case of using a tublin polymerization inhibitor as the active ingredient of an antitumor agent, the toxicity of the tublin polymerization inhibitor at the pharmaceutically effective dose can be largely relieved while maintaining the pharmaceutically effective dose and the fatal dose can be increased to thereby broaden the safety range. Moreover, antitumor methods (treatment methods for the treatment, improvement, inhibition of progress, prevention, etc. of tumor <i>in vivo</i>), use of the above two active ingredients in drugs such as antitumor agents, and combined use of the above two active ingredients as drugs such as antitumor agents either simultaneously or separately.
