The mortality response of Argentine worker ants, Linepithema humile (Mayr), following exposure to four phenolic compounds (sodium salicylate, sodium cinnamate, p-coumaric acid, caffeic acid) known to serve in plant defense mechanisms, boric acid, and sodium bicarbonate was assayed in laboratory testing. Argentine ant mortality after 3 days of exposure to sodium salicylate powder was significantly (F = 129.69; df = 3,2; P < 0.0001) higher than ant mortality in the untreated controls and in treatments with boric acid and sodium bicarbonate powders. Worker ant mortality after 3 days exposure to either sodium salicylate or cinnamic acid powder was significantly (F = 124.56, df =4,2, P < 0.0001) higher than mortality of worker ants in control, p-coumaric acid, and caffeic acid treatments. Assays with a range of concentrations (0,0.625, 1.25, 2.5, and 5.0%) of either sodium salicylate or sodium cinnamate dissolved in 10% sucrose solution showed significantly higher mortality with 5% sodium salicylate (F = 15.03; df = 4,2; P < 0.0001) and 5% sodium cinnamate (F = 30.14; df = 4,2; P < 0.0001) than the lower concentrations tested. In summary, salicylic acid and cinnamic acid, both in powder forms and liquid sucrose baits caused a higher Argentine worker ant mortality than either boric acid or sodium bicarbonate. Both appear to be promising candidates for further development as Argentine ant control products.