RT Journal A1 Thorsen WB, Jr., Western D, Tanaka Y, Morrissey JF T1 Aspirin injury to the gastric mucosa: Gastrocamera observations of the effect of ph JF Archives of Internal Medicine JO Archives of Internal Medicine YR 1968 FD June 1 VO 121 IS 6 SP 499 OP 506 DO 10.1001/archinte.1968.03640060013003 UL http://dx.doi.org/10.1001/archinte.1968.03640060013003 AB A controlled study of the acute effects on the gastric mucosa of acetylsalicylic acid in an alkaline and an acid environment was performed in healthy students. Gastric blood loss was determined by the Hemastix method and direct visual observations of the gastric mucosa were made with a gastrocamera. This study has shown that hemorrhagic lesions of the gastric mucosa are common in university students when aspirin tablets are ingested in the presence of a low intragastric pH. There were no reactions when the intragastric pH was alkaline. Gastrocamera photographs are presented to demonstrate the types of reactions which occurred. The findings suggest that it is the unionized acetylsalicylic acid rather than its sodium salt which is injurious to the gastric mucosa.