The regulation of cytokines and pro‐inflammatory genes is an absolute essentiality to combat inflammatory diseases. The present study investigated the effects of 4‐O‐chloroacetyl‐2,3‐di‐O‐acetyl‐6‐O‐levulinoyl‐β‐d‐glucopyranosyl]‐(1‐3)‐1‐O‐(p‐methoxyphenyl)‐2‐deoxy‐2‐N‐trichloroacetyl‐4,6‐O‐benzylidene‐α‐d‐glucopyranoside (RSCL‐0409), a novel small molecule Toll‐like receptor (TLR) signalling antagonist, and its mechanism of action in human monocytic (THP‐1) cells stimulated with lipopolysaccharide (LPS). In THP‐1 and RAW264.7 cells, RSCL‐0409 suppressed LPS‐induced production of tumour necrosis factor‐α (TNF‐α) with a 50% inhibitory concentration of 10.6 μm and mRNA expression of ICAM‐1, Cox‐2 and interleukin‐8 with no evidence of cytotoxicity. RSCL‐0409 also suppressed TNF‐α production from LPS‐stimulated human peripheral blood mononuclear cells. Similar results were obtained in vivo in a murine model of LPS‐induced inflammation, where pretreatment with RSCL‐0409 resulted in significant inhibition of TNF‐α. It is also noteworthy that RSCL‐0409 suppressed the cytokine production induced by TLR2 and ‐4 ligands and not for any other TLR ligands. RSCL‐0409 significantly inhibited p65 nuclear translocation induced by LPS. In conclusion, RSCL‐0409, a novel small molecule, is the first of its kind in the category of carbohydrate‐derived TLR signalling antagonists and could definitely be a promising therapeutic agent for inflammatory diseases whose pathogenesis involves TLR2‐ or TLR4‐mediated signalling processes.