Tofacitinib precursor-1 is an effective and oral active precursor to mitigate the systemic adverse effects of Tofacitinib. Tofacitinib precursor-1 can effectively attenuate the oxazolone-induced colitis in mice model with low toxicity. Tofacitinib precursor-1 is a potential drug candidate for the research of ulcerative colitis.