“The di-α-hydroxy bile acids, deoxycholic and chenodeoxycholic acids, were more gastrotoxic than cholic and ursodeoxycholic acids, and all unconjugated bile acids were … acidic then at neutral pH. Lysolecithin gastrotoxicity, comparable at neutral pH to that of chenodeoxycholic acid, was also reduced at acidic pH. Lecithin … chenodeoxycholic acid ….”