The Scottish doctor's appearance introduces the theme of disease--in Lady Macbeth and in the country--though the cause is mental rather than microbial. The unwillingness of the Gentlewoman to talk without a witness shows the state of distrust that exists in Scotland under Macbeth.

In the English court, an English doctor tells Malcolm in 3.4 about the power of the blessed English king, Edward the Confessor, to cure victims of the skin disease scrofula by his touch.