The present invention discloses a preparation method for large scale production of human immunoglobulins (IgG) with high yields by an improved all-chromatography process scheme that eliminates ethanol precipitation. The process of extracting immunoglobulins is such that the other therapeutic proteins in plasma are left unaffected and are available for extraction separately from the same plasma sample. The yields obtained are in the range of 7 to 8 grams of IgG per liter of plasma. The high yielding process scheme of the present invention comprises of chromatographic steps and viral inactivation or removal steps to obtain a purified immunoglobulin protein that complies with pharmacopoeial limits and is suitable for therapeutic administration (normal intravenous immunoglobulin—IVIG).
