Water, air, and cleanliness are the chief articles in my pharmacopoeia.

The remark encapsulates a pragmatic, almost proto–public-health view of medicine: the most reliable “drugs” are not exotic compounds but the basic conditions that prevent illness—clean water, fresh air, and hygiene. Framed as a “pharmacopoeia” (a formulary of medicines), it rhetorically elevates sanitation to the status of primary therapy. Attributed to Napoleon, it also fits the administrative mindset of a commander-emperor concerned with keeping armies and populations functional: disease historically killed more soldiers than battle, and cleanliness and ventilation were among the few broadly effective countermeasures available before germ theory and antibiotics.