It has been established that conventional root canal irrigants cause detrimental effect on the physico-chemical properties of root dentin. This study aims to determine the effect of a novel root irrigant, ginger or Zingiber officinale Roscoe essential oil on root dentin microhardness. Eighty root halves of extracted human teeth were used and prepared by embedding them individually in autopolymerizing acrylic resin. These samples were then divided into four groups (n = 20 each), i.e., i) 0.5% Z. officinale Roscoe oil, ii) 2.5% sodium hypochlorite (NaOCl, positive control), iii) 17% ethylenediaminetetraacetic acid (EDTA, positive control) and iv) normal saline (negative control). Dentin microhardness was measured using Vickers Microhardness Tester with a 50 g load and a 10-second dwell time, before and after immersion in respective solutions for 5 minutes. Measurements were taken in Vickers hardness number (VHN). All samples showed reduction in the microhardness reading; with Z. officinale Roscoe: 34.24 to 25.89, NaOCl: 31.47 to 26.34, EDTA: 33.08 to 26.04 and saline: 29.82 to 27.61 VHN. Although there was significant reduction within the Z. officinale Roscoe group (p < 0.001), the change was indifferent when compared among groups (post hoc Tukey's HSD test p > 0.05). Within the limitations of this study, Zingiber officinale Roscoe essential oil does alter dentin microhardness but to a similar extent as NaOCl and EDTA.