The lemon originated in the foothills of the Himalayas, in the region spanning northeast India, northern Myanmar, and southern China, where citrus fruits first evolved and were domesticated. From there, lemons spread along trade routes into the Middle East and were introduced to the Mediterranean by Arab traders around the 10th century, where they were initially grown as ornamental and medicinal plants before becoming a culinary staple.
Lemons became closely tied to naval history: from the late 18th century, British ships carried citrus fruit to prevent scurvy among sailors, after naval surgeon James Lind's landmark 1747 trial — one of the earliest controlled clinical trials in medical history — demonstrated that citrus fruit cured scurvy far more effectively than other tested remedies. This gave lemon and its relatives a uniquely well-documented place in the early history of evidence-based medicine.
Lemon's most talked-about modern use — fighting off colds via vitamin C — has a more limited evidence base than popular belief suggests, and it's worth being precise here. A major Cochrane review, pooling 29 trial comparisons with over 11,000 participants, found regular vitamin C supplementation had no effect on how often people in the general population caught colds. It did find a modest, consistent reduction in the duration of cold symptoms with regular (not after-the-fact) supplementation, and a more notable effect specifically in people under short-term extreme physical stress, such as marathon runners, where vitamin C roughly halved cold risk in some trials.
Importantly, taking vitamin C only after a cold has already started showed no consistent benefit for severity or duration. Lemon's uncontested historical strength remains scurvy prevention — a genuinely proven, historically pivotal use — but its evidence for treating an active cold is much weaker than commonly assumed.
Juiced fresh, added to warm water and honey for sore throats, or used as a preservative and flavoring agent in traditional preparations of other remedies (many historical "remedy" recipes use lemon primarily to make other ingredients palatable).