Abstract <p>Licorice is a perennial plant with valuable bioactive compounds such as glycyrrhizin and glycyrrhetinic acid. Biotechnology methods to increase beneficial compounds can prevent the extinction of this valuable plant. The present study was conducted to increase the number of bioactive components as a result of the stimulation of hairy root production by <i>Agrobacterium rhizogenes</i> and the use of a cellulase elicitor derived from <i>Aspergillus niger</i>. Cellulase elicitor at 100, 200, and 400 μg/mL concentration was added to 35‑day-old hairy roots. Roots were harvested 1, 2, 3, 5, and 7 days after treatment. Traits such as total phenol content (TPC), total flavonoid content (TFC), glycyrrhizin, glycyrrhetinic acid, and antioxidant activity were measured for each treatment. The results showed TPC, TFC, glycyrrhizin, and antioxidant activity reached their maximum value after two days of the treatment. The amount of glycyrrhetinic acid reached its maximum value on the fifth day. Glycyrrhetinic acid is converted to glycyrrhizin by the enzyme glucuronosyltransferase. It seems that the cellulase enzyme inhibited the activity of the glucuronosyltransferase or affected the expression of the genes that produce this enzyme and led to the decrease in the expression or silence of the genes of this pathway. Therefore, it prevented the conversion of glycyrrhetinic acid to glycyrrhizin on the fifth day after the treatment. Compared to other methods, the production of hairy root in licorice and the use of cellulase elicitor is a simpler and more efficient method and will provide a basis for the commercial production of glycyrrhetinic acid, a substance with great medicinal value.</p>