In　this　work,　the　acute　and　subchronic　toxicities　of　desaminotyrosine　(DAT)　by　oral　administration　in　SD　rats　and　its　effects　on　the　intestinal　microflora　were　investigated.　The　acute　toxicity　test　showed　that　DAT　is　a　low-toxic　substance　with　a　LD50　of　3129　mg/kg.　The　subchronic　toxicity　test　showed　that　DAT　has　no　toxicity　at　a　low　dose　(125　mg/kg/day).　However,　DAT　exhibited　obvious　toxicities　to　food　intake,　liver,　kidney,　and　lung　at　higher　dose　(250　mg/kg/day　and　500　mg/kg/day).　DAT　inhibited　the　food　intake　of　rats　in　a　dose-dependent　manner.　Serum　biochemical　analysis　showed　that　DAT　can　increase　the　serum　glucose　level　of　rats.　Fecal　microbiota　analysis　showed　that　DAT　treatment　can　significantly　change　the　intestinal　microflora　of　rats,　the　dose　of　125　mg/kg/day　has　the　most　significant　effect　on　the　diversity　of　intestinal　microbiota.　In　daily　application,　the　side　effects　caused　by　DAT　might　be　gastrointestinal　irritation,　weight　loss,　liver　or　kidney　injury,　and　blood　sugar　elevation.　Based　on　our　study,　the　no-observed-adverse-effect　level　(NOAEL)　of　DAT　is　125　mg/kg　BW/day　for　rats.