Menthol differs from other terpenic essential oil constituents.

The European Medicines Agency concluded that there is a risk of suppositories containing terpenic derivatives, which are used to treat coughs and colds, inducing neurological disorders, especially convulsions, in infants and small children. Terpenic derivatives are found in essential oils obtained from plants and include camphor, eucalyptol (syn. 1,8-cineol), thujone, and menthol. Chemistry, pharmacodynamics and pharmacokinetics of these compounds are clearly different and explain the appearance of convulsions following camphor, thujone, and eucalyptus oil overdose/poisoning, whereas no convulsions have been reported in cases of menthol overdose/poisoning in accordance with the pharmacological properties of menthol. Thus, a general verdict on all terpenic derivatives without differentiation appears inappropriate.