Eucalyptus, recognized for its distinctive aroma and use in medicinal products, can be poisonous to humans. The severity of poisoning depends on the form and amount consumed, as the plant contains compounds that are toxic when ingested in sufficient concentration. Careful handling and storage are required to prevent accidental exposure.
The Toxic Compound: Eucalyptol and Its Effects
The primary toxic agent in eucalyptus is 1,8-cineole, or eucalyptol, a monoterpenoid compound present in high concentrations in the essential oil. This colorless organic compound is highly lipid-soluble, allowing it to pass easily through cell membranes and be rapidly absorbed. Once in the bloodstream, eucalyptol targets several major physiological systems, causing systemic toxicity. Its effects are noticeable in the central nervous system (CNS), respiratory tract, and gastrointestinal tract. In the CNS, eucalyptol acts as a depressant, which can lead to rapid alteration of consciousness. In the respiratory system, the oil can cause direct irritation and injury, particularly if inhaled into the lungs during ingestion, known as aspiration pneumonitis.
Toxicity Levels: Leaves Versus Concentrated Oil
The risk of poisoning is directly related to the concentration of 1,8-cineole and the amount ingested. Eucalyptus leaves contain a lower concentration of the toxin; therefore, ingesting a small piece of a leaf is unlikely to cause severe poisoning in a healthy adult, though mild gastrointestinal upset may occur. The essential oil, which can contain up to 90% eucalyptol, poses the most significant danger, especially for children. Ingesting a small amount of the concentrated oil can be life-threatening, with serious symptoms anticipated after just 5 milliliters (approximately one teaspoon) of the pure oil. Minor depression of consciousness has been reported following the ingestion of as little as 2 to 3 milliliters in children. Due to their lower body weight, children are particularly vulnerable to concentrated eucalyptus oil. Ingestion of 3.5 to 5 milliliters has been reported as the lethal dose in some adult cases, highlighting the severe toxicity of the pure substance. Products containing the oil must be stored securely to prevent accidental ingestion.
Recognizable Symptoms of Eucalyptus Poisoning
Symptoms of eucalyptus oil poisoning can appear rapidly, often within 30 minutes of ingestion, though onset may be delayed up to four hours. Initial signs involve the gastrointestinal system, including a burning sensation in the mouth and throat, nausea, vomiting, and abdominal pain. Diarrhea may also occur. As eucalyptol is absorbed, it affects the nervous system. Mild central nervous system effects include drowsiness, dizziness, slurred speech, and ataxia (loss of muscle coordination). Larger ingestions can progress to severe central nervous system depression, manifesting as confusion, deep unconsciousness, and coma. Seizures are a serious complication that occurs more frequently in children following exposure. Respiratory failure is also a risk, resulting either from direct depression of the brain’s breathing center or from chemical injury to the lungs caused by aspiration.
Immediate First Aid and Medical Management
If eucalyptus oil ingestion is suspected, immediate action is necessary. Contact a local emergency number or the national Poison Help hotline (1-800-222-1222 in the United States) for expert guidance. Provide the poison control center with the person’s age, weight, the product name, and the estimated amount and time of ingestion for an accurate assessment. Do not induce vomiting unless specifically instructed by a medical professional or the Poison Control Center. Inducing vomiting increases the risk of the oil being aspirated into the lungs, which can cause severe, life-threatening chemical pneumonitis. If the oil touched the skin or eyes, flush the area thoroughly with water for at least 15 minutes. Treatment at a medical facility is primarily supportive, as there is no specific antidote. Medical management focuses on monitoring the patient’s vital signs, including heart rate, blood pressure, and breathing. Supportive care involves providing intravenous fluids and managing symptoms like seizures. In severe cases involving respiratory compromise or deep coma, the patient may require breathing support, such as a ventilator.