Stop use if the clove oil is too strong, upsets your stomach, or burns. Clove oil contains the active ingredient eugenol, a natural anesthetic. Eugenol helps numb and reduce pain to ease a toothache.
Effects of root-end filling materials and eugenol on mitochondrial dehydrogenase activity and cytotoxicity of human periodontal ligament fibroblasts J Biomed Mater Res B Appl Biomater 2004;71:429-440.