The present invention provides a method to induce maturation of an immature GI-tract, such as intestine, e.g. small intestine, the method comprising the steps of administering a mixture of enzymes to the immature GI-tract, said enzymes having a pancreatic activity or action, and/or pancreatic like activity or action, and analyzing the maturation process of the GI-tract to monitor said maturation process. Provided herein are also uses and kits to provide for GI-tract maturation.
