In this article, the effectiveness of cellulase treatment on linen was evaluated by means of phenol-sulfuric acid method. This method was performed by determining sugar liberation in the treatment bath with the amount expressed in glucose equivalence. As compared with conventional method, the measurement of amount of sugar liberated gave a more reliable and accurate result than the weight loss method. It was found that although weight loss of cellulose became negligible when the treatment was done under agitation-free condition, the amount of sugar liberated was still readily measurable. (c) 2007 Wiley Periodicals, Inc.