Colorectal　lateral　spreading　tumours　(LST),　early-stage　lesions　of　colorectal　cancer　(CRC),　are　associated　with　gut　microbiota　dysbiosis.　However,　the　functional　alterations　in　gut　microbiota　and　their　metabolic　pathways　remain　inadequately　understood.　This　study　employed　propensity　score　matching　to　compare　35　LST　patients　with　35　healthy　controls.　Metagenomic　and　metabolomic　analyses　revealed　notable　differences　in　gut　microbiota　composition　and　metabolic　pathways.　LST　patients　exhibited　a　marked　reduction　in　short-chain　fatty　acid　(SCFA)-producing　probiotics,　such　as　Roseburia,　Clostridium,　and　Butyricicoccus　sp-OF13-6,　alongside　anti-inflammatory　metabolites.　In　contrast,　potential　intestinal　pathogens　linked　to　inflammatory　bowel　disease　(IBD),　including　Escherichia　and　Citrobacter　amalonaticus,　were　significantly　enriched.　Orthogonal　partial　least　squares　discriminant　analysis　(OPLS-DA)　highlighted　significant　metabolic　disparities　between　the　groups,　with　enrichment　in　pathways　associated　with　cholesterol　metabolism,　choline　metabolism　in　cancer,　and　amino　acid　metabolism　-　all　relevant　to　cancer　progression.　Key　biomarkers　identified　for　LST　included　fumarate,　succinate,　glutamic　acid,　glycine,　and　L-aspartic　acid,　which　were　closely　linked　to　these　pathways.　Functional　studies　demonstrated　that　these　metabolites　promoted　the　proliferation　and　invasion　of　HCT-116　and　SW480　human　colorectal　cancer　cells　in　vitro.　Metagenomic　and　metabolomic　analysis　revealed　a　strong　positive　correlation　between　Escherichia　and　Ruminococcus　sp-AM41-2AC　abundance　and　the　enriched　pathways,　whereas　reductions　in　Roseburia　species,　including　Roseburia-OF03-24　and　Roseburia　intestinalis_CAG13-exhibited　negative　correlations.　These　results　suggest　that　gut　microbiota　and　metabolite　alterations　in　LST　contribute　to　intestinal　inflammation　and　CRC　development,　underscoring　their　potential　as　biomarkers　for　early　detection　and　therapeutic　targets.