PROBLEM TO BE SOLVED: To provide an extract of inflamed skin in a vaccine virus-inoculated rabbit, more stable in quality and a preparation containing the extract as an active ingredient.SOLUTION: By using, as an indicator, the amount of n-acetylneuraminic acid contained in the extract of inflamed skin in a vaccine virus-inoculated rabbit and the preparation containing the extract as an active ingredient, more stable quality of the extract and the preparation can be ensured. The effectiveness and the safety of the extract of inflamed skin in a vaccine virus-inoculated rabbit and the preparation containing the extract as an active ingredient, whose quality is more stable by such method, are strictly ensured. Thus, the extract and the preparation has really high utility.
