John Scantlebury Blenkiron is a fictional character who appears in several books by John Buchan, including Greenmantle, Mr Standfast, The Courts of the Morning and Sick Heart River. Blenkiron comes from the United States, and has assisted Richard Hannay. When Hannay first meets Blenkiron, it is revealed that he suffers from dyspepsia and so often drinks boiled milk, eats dry toast and fish. Subsequently he has an operation where a part of his duodenum is replaced by rubber tubing and his digestion is restored.