Cedar oil has a sweet, woodsy smell and is used for aromatherapy, in scented products, as a food additive and for pest control. However, its sweet smell may be misleading—it isn’t completely benign. It is possible to consume toxic levels of cedar oil, and the damage can be significant. Still, because of its many uses and low toxicity compared to substances such as Deet and moth balls, it remains a popular household item and manufacturing ingredient.
Toxicity in Humans
Cedar oil is considered by the Environmental Protection Agency (EPA) to be a generally safe substance because humans are not likely to be exposed to more than a minuscule amount of cedar oil, and they are even less likely to ingest it except in small amounts as a food additive. Still, children may be tempted to drink the oil because of its pleasant scent. Consumption of a significant amount of the oil may cause hyperactivity, negative respiratory and gastrointestinal effects, a loss of vision, pain in the eyes, ears and throat and even seizure or coma. According to the University of Maryland Medical Center, the best thing to do if a person notices these symptoms is to give the person with toxic exposure water or milk to drink if they can easily swallow, and to immediate call a poison control center at 800-222-1222 (see Resources).
Thujone is the substance in cedar oil suspected to cause any potential toxic effects. Thujone is also considered the psychoactive substance in the alcoholic beverage absinthe, which has been used for clarity of mind by artists, writers and poets through the last several hundred years, according to AbsintheFever.com. Wormwood, which is an ingredient in absinthe, is 40 percent thujone by weight, and cedar oil contains between 0 percent and 61 percent thujone, depending upon its sources—Texas cedar oil is in the 60 percent range. Today, thujone is used by herbalists, who prescribe wormwood as a mind-clarifying herb.
Use Against Pests
Cedar oil can be used against pests like fleas and mosquitoes, but not because it is toxic. Rather, the smell of it triggers an unfavorable feeling in these insects by disrupting their pheromone patters. The octopamine neural receptors of the pests are affected, according to Insect-Collection.com. Cedar oil can be diluted and used on dogs against fleas, or on humans against mosquitoes. Lavendar, lemongrass and citronella oil all compliment the insect-repelling effect of cedar oil when mixed in a non-irritating base like almond oil.
Use Against Parasites
Cedar oil is able to kill and disable parasites. According to a 2005 study carried out by researchers at the Johns Hopkins Bloomberg School of Public Health, cedar oil was able to kill larva of the parasite Schistosoma mansoni larvae, and its addition to the surface of a swimming pool reduced its infectious ability by 99.2 percent.
More studies are needed concerning just how toxic cedar oil can be. According to both the EPA and National Institutes of Health, cedar oil doesn’t constitute an immediate threat. However, it is not completely understood. Its abortificant properties need further study, as does its overall toxicological profile (see References 4).