For the reasons above, the up-regulated CYP1A1, SLC6A4, SLC6A8, PHLPP2, ANO1, NR1D1, CPA6, GLP-2R, GSTT1 and SlCO2A1 in mEV−fed mice indicated that mEVs facilitated the expression of genes that had low expression in colitis, and hence ameliorated colitis. The gene discussed is CYP1A1; the disease is colitis.