To the Editor:

We read with interest the article by M. Al-Zubaidy et al. [1] and would like to clarify the correct usage of the Caduceus and Asclepius (or Aesculapius) symbols.

Al-Zubaidy et al. utilised the Caduceus, which is often used in place of the Rod of Asclepius despite their very different meanings. The Caduceus is the staff of Hermes, the messenger god [2], and has been mistaken for the Rod of Asclepius, a symbol of medicine for over a hundred years. Hermes was a patron of negotiation, trade, and commerce [3]; his trusty staff, the Caduceus, came to be a symbol for the god himself and is seen printed on Roman coins.

Caduceus is a symbol with an often-winged staff entwined by two serpents surmounted by wings. The Rod of Asclepius is a symbol with a rod entwined by only one serpent. The Rod of Asclepius belongs to the Greek god of healing and medicine, Asclepius [3]. For over one hundred years the Caduceus has been wrongly used as a medical symbol due to its visual similarities with the Rod of Asclepius (Fig. 1).

Fig. 1
figure 1

The Caduceus (left) and the Rod of Asclepius (right).

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The Caduceus was first documented being incorrectly used as a medical symbol in the 1850s when it was applied to US Army hospital stewards [4]. A survey in 1992 found 76% of US hospitals were likely to misuse the Caduceus, while Shetty et al. found that only 6% of doctors were aware that the Rod of Asclepius was the true symbol of healing [5].

In the United States it is common to see the Caduceus used as a symbol of medicine e.g., on the flag of the US Surgeon General (Fig. 2). In 1902 the Caduceus was added to the uniforms of US army medical officers.

Fig. 2
figure 2

A Montegrappa “Medical Pen” (left); the flag of the US Surgeon General (top right); the symbol of the World Health Organization (lower right).

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The Montegrappa “Medical Pen” line features the Caduceus while acknowledging the Rod of Asclepius on their website (Fig. 2).

We found no instances where the Rod of Asclepius was mistaken for the Caduceus.

The Caduceus is correctly used by the Customs Agency of Bulgaria, the Financial Administration of the Slovak Republic, and the Chinese Customs.

Finally, we are delighted to note that the British Medical Association and World Health Organization correctly use the Rod of Asclepius in their logos (Fig. 2).