Abstract: A medical honeycomb structure lacking at least a portion of an outer peripheral side wall of a honeycomb structure that includes a plurality of through-holes extending in one direction, wherein sites lacking the outer peripheral side wall have a plurality of grooves, and have a plurality of planes including distant surfaces of groove side walls flanked by the grooves.

Abstract: Provided is a medical calcium carbonate composition that highly satisfies 1) tissue affinity, 2) in vivo resorbability, 3) reactivity, and 4) mechanical strength required for medical materials to be implanted in vivo, a medical calcium phosphate composition, a medical carbonate apatite composition, a medical calcium hydroxide porous structure, a medical calcium sulfate setting granules, and a bone defect regeneration kit related to the medical calcium carbonate composition, and methods for producing these. The medical composition calcium carbonate that highly satisfies the above described elements, and related medical compositions can be produced by controlling the polymorph or structure of calcium carbonate.