At the turn of XIX and XX century, the principal concept explaining the mechanism of secretory activity of the digestive glands was nervism proposed by I. P. Pavlov at Russian physiological school in St Petersburg, and this dogma was widely recognized for several years in other countries. The discovery of secretin in 1902 by W.B. Bayliss and E.H. Starling, and then of gastrin in 1906 by J.S. Edkins, emphasized the hormonal regulation of pancreatic and gastric secretion, respectively. In 1943, A.C. Ivy and E. Olberg discovered a hormone, which contracts the gallbladder - cholecystokinin (CCK), while A. Harper and H.S. Raper described another hormone, pancreozymin, which stimulated pancreatic enzymes. It required over twenty years, however, for these and many other hormones to be identified, purified and synthesized due to the extensive work of several teams including R. Gregory, G. Dockray and Kenner of the UK; J. Rehfeld of Denmark and E. Wunsch of Germany for their work on gastrin; E. Jorpes and V. Mutt of Sweden and N. Yahaihara of Japan for their work on secretin and other GI hormones including, CCK, vasoactive intestinal peptide (VIP), gastric inhibitory peptide (GIP), motilin, gastrin-releasing peptide (GRP) and others peptides. CCK and pancreaozymin were found by E. Jorpes and V. Mutt to represent structurally a common messenger for pancreatico-biliary secretion. This rapid development of GI endocrinology in the 1960s and 1970s could be attributed to the application of peptide biochemistry in characterizing various peptide hormones. The technique of radioimmunoassay by S.A. Berson and R.S. Yalow in 1959 measured minute amounts of hormones in the circulation and tissue, and the technique of immunocytochemistry detected the cellular origin of these hormones. Further progress in molecular biology led to sequencing GI hormones and their prohormones, and opened a new area of investigation for the physiological role of these hormones in the mechanism of digestive gland secretion, motility of gastrointestinal tract, visceral blood flow, tissue growth and integrity in health, as well as in various digestive diseases. Overall, apparent divergent concepts, the nervous control (Pavlov) and hormonal control (Bayliss and Starling), greatly facilitated the elucidation of the interacting neurohormones during the cephalic, gastric, and intestinal phases of gastric and pancreatic secretion in health and digestive diseases. Although Polish contributions in the early phase of GI endocrinology concerned mostly gastric inhibitory hormones such as enterogastrone and urogastrone, major Polish traces can be detected in the elucidation of origin and physiological role and pathological involvement of gastrin, CCK, secretin, motilin, gastric inhibitory peptide and the most recent additions of enterohormones such as epidermal growth factor, somatostatin, leptin or ghrelin. Major achievements have been obtained in gastric and colorectal cancerogenesis involving gastrin and its precursor, progastrin.