Abstract: Blood products and derivatives, such as procoagulants--e.g. Factor VIII and rothrombin--plasma proteins, immunoglobulin and complement growth factors and various leucocytes, are obtained from shed blood or its tissue precursor, bone marrow, that has been anticoagulated by the use of a neutral salt that does not bind calcium ions. The preferred anticoagulants are salts containing the divalent ions calcium, magnesium, barium or strontium. Salts of calcium and magnesium are especially preferred because of their relatively lower toxicity, the salt of choice being a magnesium salt, for instance magnesium chloride, because magnesium salts exhibit the required anticoagulating action at levels compatible with retention of normal ionic strength and osmolarity. The toxicity of the neutral salt is eliminated by its removal.