Hygiene Institute, Department of Virology, University of Heidelberg, Im Neuenheimer Feld 324, Heidelberg, Germany. Paul_Schnitzler@med.uni-heidelberg.de
Acyclovir-resistant clinical isolates of herpes simplex virus type 1 (HSV-1) were analyzed in vitro for their susceptibilities to essential oils of ginger, thyme, hyssop, and sandalwood. All essential oils exhibited high levels of virucidal activity against acyclovir-sensitive strain KOS and acyclovir-resistant HSV-1 clinical isolates and reduced plaque formation significantly.