Anti-Aphrodisiac

You find a box in the attic.

Ready-for-retail-sale bottles are stacked in this box.  They are labeled “Purity Pills”.  A stack of papers lies atop the bottles.  The papers give the chemical formula for the pills, directions for synthesis, and explain that any man who swallows a pill will have perfect rational control over his libido.

A note on top of the stack reads: “If this gets out, we’re ruined.  — H. H.”