The invention provides a particle consisting essentially of micronized ESM and having a mean particle diameter of less than 100 µm for use in promoting the healing of a chronic wound at risk of, or in which there is, (i) an inappropriate level of matrix-metalloproteinase (MMP) activity against extracellular matrix (ECM) proteins and/or peptide growth or differentiation factors, and/or (ii) an excessive inflammatory response. The invention further provides pharmaceutical compositions, wound dressings and implantable medical devices comprising the micronized ESM-containing particles for use in said treatments. The invention still further provides methods for manufacturing the micronized ESM-containing particles and the compositions, dressings and implantable medical devices comprising the same.