Abstract: The present invention is directed to medical or dietary treatments comprising administration of a zymogen such as chymosin or other rennins. Embodiments of the invention are directed to treating infant colic, heartburn, gastro-esophageal reflux (GER), gastro-esophageal reflux disease (GERD), irritable bowel syndrome, and recurrent abdominal pain. The invention is also directed to improving absorption of calcium from milk for osteoporosis patients. Further the present invention may have a very positive effect on life quality for groups with different chronic digestion problems such as ulcerous colitis, multiple sclerosis, migraines, weight disorders and diabetes. Infants may be given several drops of a composition containing chymosin prior to every feeding, regardless of whether they are bottle or breast-fed. The composition containing chymosin can also be incorporated into a food product such as drinking milk or baby formula.