Septic shock is a leading cause of mortality in intensive care patients, and no specific drugs are as yet available for its treatment. Therefore, new leads ar e required in order to increase the numbe r of active molecules that may develop into efficacious and safe LPS-neutralizing mol ecules during pre-clinical stages. We used pe ptides, derived from the binding regions of known LPS-binding proteins, as scaffolds to introduce modifications at the amino aci d level. Structure–activity relationship studies have shown that these modifications generate highly acti ve peptides. Thus, from a bioactive peptide with an initial 16 amino acid residues, a tetrapeptide sequence was determined. A fter inserting this sequence in a Cys cyclic peptide, it showed the same biological activity as the parent peptide. This sequenc e could provide the basis for the design of small molecules with LPS-binding properties ; Peer Reviewed ; Postprint (published version)