The Scottish physician who conducted the first controlled clinical trial in 1747 was James Lind. His famous experiment tested possible treatments for scurvy among sailors in the British Royal Navy.
While serving as a ship's surgeon, Lind selected twelve sailors suffering from scurvy and divided them into six pairs. Each pair received the same basic diet but a different supplement, including cider, vinegar, seawater, sulfuric acid, a medicinal paste, or citrus fruit. The sailors given two oranges and a lemon improved dramatically, with one soon fit for duty and the other nearly recovered.
Lind published his findings in A Treatise of the Scurvy in 1753. He correctly demonstrated the value of citrus, although he did not identify vitamin C, which would not be understood until much later. Nor was he the first person to suggest citrus as a possible remedy; his importance lies in testing alternatives systematically under controlled conditions.
The experiment was not a modern randomized clinical trial. It used only twelve participants, and Lind's conclusions were not immediately adopted by the Navy. Nevertheless, it became a landmark in the history of clinical research and evidence-based medicine.