An essential oil from the blue gum-tree, is regarded as an antiseptic, and is in favour where insanitary conditions predispose horses to fever and impart an unhealthy condition to wounds. Septicaemia, strangles, influenza, and purpura are among the diseases in which eucalyptus is advantageously employed for disinfecting purposes, both by inhalation and as an outward application.

Thymol is a crystalline substance derived from oil of thyme, but has not been used to any extent in veterinary medicine.

Menthol is another concrete volatile oil but seldom found in the veterinarian's pharmacy. It is, however, a powerful antiseptic, and may be substituted for iodoform where the odour of that drug is particularly objectionable.

Sanitas, so much appreciated in great studs and horse repositories where a disinfectant and deodorizer are both in request, is a proprietary preparation, its properties being due to eucalyptus and a species of pine oil.