Eugenol is a local anaesthetic AND a severe irritant. When you apply it to a tooth and it comes in contact with the gum both end up numb. Until it wears off and

Eugenol is a local anaesthetic AND a severe irritant. When you apply it to a tooth and it comes in contact with the gum both end up numb. Until it wears off and you have what amounts to chemical burns on your gums. Using eugenol to treat tooth sensitivity isn't worth it. Do NOT try using eugenol for tooth sensitivity.