Symbolism, Imagery, Allegory
When Moody needs some medicine for Abraham, Doc Conover won't sell it to her because she's Black. Ben can't get his hands on any either because he's friends with her, and yet when men storm the Quarter with guns and pitchforks hunting Ben down, Aunt Henry is the first to patch up their wounds up. As Ben considers, "Aunt Henry would take care of anyone, I reflected, regardless of race, creed, or degree of idiocy" (136.7). You know, like any decent human being would.
Because we see medicine denied to Moody and Ben for racist reasons, and then we see Aunt Henry refusing to participate in racism by treating even the racists with medicine, ointments and oils and such come to represent what people believe. Aunt Henry, for instance, willingly helps anybody who needs it, nursing Ben, Abraham, and the White Raiders back to health. On the other hand, there are many white citizens in town who will only help white people.
If we take a step back, something bigger emerges: The white people who deny Black people medicine are preventing healing, and they're part of the disease of racism plaguing Eudora. The Black people who help anyone in need, however, are like medicine in their own right, prioritizing healing over hatred time and again.