<p>Our team stands to develop a more favorable treatment experience. Relevant studies have shown that lactic acid has an inhibitory effect on abnormally activated dendritic cells and cytotoxic T-cells in autoimmune diseases, and thus is expected to improve the symptoms of IBD patients. Based on the research, we designed a yeast engineered bacterium. We introduced a muscone detecting switch in the engineered yeast and activated the downstream pathway to express lactate dehydrogenase to produce lactic acid. Ultimately, the engineered bacteria will colonize the small intestine, enabling the patient to treat IBD by inhaling muscone gas in vitro therefore induces the yeast to synthesize a low amount of stabilized lactic acid in vivo. Aroma therapy has the potential to be a new trend in long-term treatment for IBD as it can reduce the discomfort of treatment and improve the long-term treatment experience.</p>