In this article, nanofibrous mats of poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) with different PLA/PEG ratios were prepared by solution blow spinning. Terpinen-4-ol, a major phytoconstituent from tea tree oil (Melaleuca alternifolia) was added to the fibers and their antimicrobial activity against Aggregatibacter actinomycetemcomitans (ATCC 00078) was tested. Spun mats were characterized by scanning electron microscopy, thermogravimetric analyses, differential scanning calorimetry, Fourier-transform infrared spectroscopy (FTIR), and cell viability tests by biofilm grown on the surface of inhibitory fibers. Fibers had average diameters dependent on polymer ratio. PEG acted as a plasticizer resulting in a reduction in PLA crystallinity. Addition of PEG lead to a faster drug release. Fibrous mats with terpinen-4-ol, whose incorporation was verified by FTIR, showed an effective antimicrobial activity against A. actinomycetemcomitans, similar to those containing 0.12% chlorhexidine gluconate (P < 0.05), used as both the positive control and the dose level recommended for patient treatment. These results confirm the potential of solution blow spun fibrous mats containing terpinen-4-ol in the treatment of aggressive periodontitis. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45782.