Tea tree oil, also known as melaleuca oil, is an essential oil from the leaves and terminal branches of the tea tree (Melaleuca alternifolia). Tea tree oil may be perceived as a ‘natural’ treatment and has been used in pets to treat and prevent flea infestations, to treat various skin conditions and on wounds. It may be attractive to owners who prefer not to use ‘chemical’ treatments.

Pure tea tree oil should never be applied directly to the skin or fur, or given orally. Even a few drops of 100% tea tree oil applied dermally can cause clinical signs in companion animals. Signs include salivation, depression, lethargy, paresis or weakness, ataxia, tremor or muscle fasciculation, vomiting, coma, collapse or recumbency, dermatitis, pruritus or rash  and raised liver enzymes. Even a few drops on the skin can cause adverse effects and deaths have been reported in companion animals after skin application of tea tree oil.

Treatment is supportive and any pure essential oil on the skin should be washed off promptly with detergent and water.

Tea tree oils is not just a risk to cats and dogs; a recent report described tea tree oil toxicosis in a cockatiel.