Abstract: Heparin-binding peptides are provided of the formula R1(X1B1B2X2B3X3Y1R2)nR3, R1(X1B1B2B3X2X3B4X4Y1R2)nR3, and C(X1B1B2B3X2X3B4X4)nC; wherein X1, X2, X3, and X4 are independently selected from the group consisting of hydropathic amino acids; B1, B2, B3, and B4 are independently selected from the group consisting of basic amino acids; C is cysteine; Y1 is zero or one to ten amino acid residues, wherein at least one amino acid residue is proline; n is an integer from one to ten; and R1, R2, and R3 are independently selected segments containing from zero to twenty amino acid residues, provided, at least one of the segments R1, R2, and R3 comprises at least one hydrophobic amino acid residue. The peptide C(X1B1B2B3X2X3B4X4)nC is optionally cyclized via a disulfide bond formed between cysteine residues. The peptides are administered to reduce plasma LMWH and heparin levels and to reduce the anticoagulant effects of heparin and LMWH.