A composition kit for bone healing medical treatment, comprising partially deacetylated chitin (PDC) with a degree of deacetylation in the range of 40-75%. The composition is provided as a kit with a solids fraction and a liquid fraction, provided in separate vials and to be mixed just prior to use. The weight:weight ratio of the solids to liquid fraction is in the range from 1:1.2 to 1:6, and preferably from 1:1.5 to 1:4.The solids fraction comprises the PDC material and calcium phosphate and the liquid fraction comprises water and an acid.
