Indeed. I'm a historian of medicine and sometimes think that premodern healers get a bad rap. Yes, some of the cures you find in medieval or early modern medicine are absurd (like "bleeding until syncope"). But once in awhile you run into something like this, from a 17th century Portuguese physician named Duarte Madeira Arraiz:

"They spread the sickness throughout the world, each army bringing it to its respective country... and it was related by Christopher Columbus of his discoveries in the Occidental Indies to the King of Spain, that in the lands he discovered he encountered many Indian men and women who suffered from the disease of the morbo gallico [syphilis], and so those among the soldiers and men of arms who had communication with the Indian women and with the 'mulheres publicas' of the land easily spread this contagion to the greater part of the Spanish army, and from thence, to the French."

He comes pretty close to anticipating germ theory here, arguing that syphilis was sexually transmitted and correctly theorizing that it had New World origins and was spread by European colonization. These people weren't dumb.