Since previous studies have suggested several targets to improve prognosis of stroke including inhibitors of TDO, KMO, NMDAR, oral melatonin which shows efficacy of reducing the severity of stroke and improve cognitive symptoms and AhR is thought to be a potential therapeutic target for tightly participating in “gut microbiota-TRP-brain” axis in ischemia stroke treatment. This evidence concerns the gene TDO2 and Stroke.