A ship's surgeon cured scurvy with citrus in one of history's first controlled trials

In 1747, aboard HMS Salisbury, James Lind took twelve sailors sick with scurvy, split them into six pairs, and gave each pair a different remedy — cider, vinegar, seawater, citrus and more — on an otherwise identical diet. Only the citrus pair recovered dramatically within days. It took the Royal Navy another 40-plus years to make citrus rations standard, but Lind's design is now considered one of the first true clinical trials.

— James Lind, A Treatise of the Scurvy — 1753 — public domain