Clove oil is a natural product, derived from the Eugenia caryophyllata tree. Clove oil is 85 to 95% eugenol. Isoeugenol and methyleugenol make up 5 to 15% of the remaining ingredients. Isoeugenol is manufactured from eugenol by a process of isomerization. Isoeugenol have been used in foods and eugenol has been used in animal feeds. Isoeugenol is used as a fish anesthetic. The mechanism of action of isoeugenol in fish has not been determined. It is hypothesised that its effects are mediated via receptors controlling cellular ion channels in a similar way to that described for local anaesthetics. Reports of adverse reactions involving the use of isoeugenol in humans are primarily confined to incidents of contact sensitization or allergy following dermal exposure.