A process of preparing a double-sterilized immunoglobulin product for intravenous injection includes dissolving Cohn's component II in distilled ice water, and adjusting to the desired pH using acetic acid. A filter is used to remove alcohol and salt and establish a desired sodium ion concentration, and the immunoglobulin concentration is adjusted to form interim product, which is bottled. The bottle is filled with gaseous carbon dioxide to achieve a pressure of 0.7 to 200 kPa, sealed in the absence of any protectant, and sterilized. The interim product is filtered, concentrated to achieve an immunoglobulin concentration of 5% to 10%, adjusted to a desired pH, filtered to remove bacteria, and stored at room temperature for 21 days. Glucose is added in order to change the osmotic pressure equilibrium of said interim product to form final product.