late 14c., "make aromatic smoke as part of a ceremony," from Old French fumigation, from Latin fumigationem (nominative fumigatio) "a smoking," noun of action from past participle stem of fumigare "to smoke," from fumus "smoke, fume" (see fume) + root of agere "to drive" (see act (n.)). Sense of "exposure (of someone or something) to aromatic fumes" is c.1400, originally as a medicinal or therapeutic treatment.
fumigate fu·mi·gate (fyōō'mĭ-gāt')
v. fu·mi·gat·ed, fu·mi·gat·ing, fu·mi·gates
To subject to smoke or fumes, usually in order to exterminate pests or disinfect.