S34	S9 AND S32 AND S33
S33	(infan* OR newborn OR neonat* OR premature OR low birth weight OR VLBW OR LBW) AND (randomized controlled trial OR controlled clinical trial OR randomized OR placebo OR clinical trials as topic OR randomly OR trial OR PT clinical trial)
S32	S13 OR S16 OR S21 OR S24 OR S27 OR S29 OR S31
S31	S26 AND S30
S30	stomach mucosa*
S29	S26 AND S28
S28	Gastric mucosa*
S27	S25 AND S26
S26	protect* AND ( agent* OR drug OR medicine OR medication )
S25	Gastro* AND mucosa*
S24	S22 OR S23
S23	sucralfate or sulfate or antepsin or carafate or ulcerban or ulcogant or ulsanic
S22	(MH "Sucralfate")
S21	S17 OR S18 OR S19 OR S20
S20	aluminum or aldrox or algeldrate or alhydrogel or alugel or amphojel or basalgel or brasivil or dialume or nephrox or pepsamer or rocgel OR "calcium carbonate" or aragonite or calcite or "calcium milk" or Chalk or limestone or marble or vaterite OR magnesium or brucite or magnesia OR "aceglutamide aluminum" or "alexitol sodium" or algicon or Almagate or almagel or alubifar or alugastrin or andursil or attapulgite or bicarbonate or carbex or "dihydroxyaluminum sodium carbonate" or gaviscon or hydrotalcite or magaldrate or Mylanta or novaluzid or rennie or solugastril or titralac or vangatalcite
S19	( alkalinizing OR antigastralgic ) AND agent*
S18	antacid* OR bismuth
S17	(MH "Antacids+")
S16	S14 OR S15
S15	“proton pump inhibitors” OR “proton pump inhibitor” OR PPI* OR omeprazole or losec or nexium or prilosec or rapinex or zegerid or ocid or Omepral or Omez OR Esomeprazole OR Nexium OR Alenia OR Nexiam OR lansoprazole OR lanzoprazole OR agopton OR Levant OR lanzor OR prevacid OR takepron OR zoton OR pantoprazole OR protium OR protonix OR Pantozol OR Pantor OR Pantoloc OR Controloc OR ilaprazole OR rabeprazole OR aciphex OR dexrabeprazole OR pariet OR Dexlansoprazole OR Kapidex OR Dexilant OR tenatoprazole OR benatoprazole
S14	(MH "Proton Pump Inhibitors+")
S13	S10 OR S11 OR S12
S12	Burimamide OR Cimetidine OR ebrotidine OR etintidine OR Famotidine OR lafutidine OR loxtidine OR Metiamide OR mifentidine OR Nizatidine OR oxmetidine OR Ranitidine OR "roxatidine acetate" OR tiotidine OR zolantidine
S11	histamine AND h2 AND antagonist
S10	(MH "Histamine H2 Antagonists+")
S9	S1 OR S2 OR S3 OR S4 OR S5 OR S6 OR S7 OR S8
S8	gastric AND mucos* AND lesion*
S7	(MH "Peptic Ulcer+")
S6	(MH "Gastritis+")
S5	hematemesis OR haematemesis
S4	(MH "Hematemesis")
S3	Hematochezia*
S2	gastrointestinal AND ( bleed* OR hemorrhag* OR haemorrhag* )
S1	(MH "Gastrointestinal Hemorrhage+")