Officials from the Tennessee Poison Control Center have issued a warning about toxic exposures from essential oils, which are often used in homeopathic natural remedies and aromatherapy.
The number of toxic exposures from essential oils reportedly doubled between 2011 and 2015, with 80 percent of those cases involving children, according to The Associated Press.
The essential oils included in the TPC's warning include thyme, tea tree, eucalyptus, lavender, wintergreen, clove and camphor oil, which the TPC said are toxic when ingested. Children can also choke on the oils, the TPC says.
Children are at greater risk than adults for toxic exposure because their skin can more easily absorb the oils. While ingestion is the main method of exposure cited by the TPC, applying too much of the oils to the skin can also be harmful.
"The rule of thumb in toxicology is 'the dose makes the poison,' so all essential oils are potentially harmful," said Dr. Justin Loden, a specialist from the TPC, according to HealthDay.
"In children, poisoning typically occurs when they try to swallow the oil, but choke so that a little of it goes into the lungs, which causes pneumonia," said Loden in a news release for Vanderbilt University. "It only takes less than half a teaspoonful to do that. This hazard applies to every essential oil."
Loden added that "tea tree oil is commonly cited, and most of those cases are accidental ingestions by children."
The National Capital Poison Center recommends that people who use essential oils use them according to the instructions on the label only, and to stop use immediately if a rash or other skin reaction is discovered. The site also advises that the oils may interact with other drugs.
Many essential oils can cause serious symptoms, including chemical burns, liver failure, seizures, hallucinations and breathing problems. According to the NCPC, nutmeg can cause hallucinations if too much is ingested, and sage oil has been reported to cause seizures in children.
Essential oils' effects can vary depending on the plant, making it imperative to know which plants are used in an oil. For example, peppermint is a type of mint that is used to ease gastrointestinal discomfort. But oil made with pennyroyal, another type of mint, is highly toxic to the liver.
In general, essential oils are not regulated like medicines, so concentrations and species of plant can vary from brand to brand, making it harder to know exactly what is inside a given bottle.
Loren recommends that parents and pet owners lock their essential oils out of their child or pet's reach. If a child ingests an essential oil, Loden advises parents to call Poison Control.