1a enter upon certain rituals intended to gain the help of the gods in warding off evil or sickness, in ensuring a good hunt or successful war, in bringing harm to enemies, etc.
1802  (1897)  An Indian made medicine to ask his Manitou whether a certain sick person would recover.
1896  They thought we were making "medicine" against them, but were won over by Heming drawing the moose and the caribou, while they watched the animals they knew so well develop under his pencil.
1923  The medicine man makes medicines (i.e., symbols, or inimical thoughts) against a man, and promptly that unlucky individual falls ill.
1bFigurative use See quotes.
1956  When I dropped around to make medicine with him, the girl in the office told me he had left the Company.
1957  "If he [an angry bull] makes medicine, so will I!" retorted the postie.