The common name “laurel” is broadly applied to a variety of distinct plant species, leading to confusion about whether these plants are safe or toxic to handle. While many common ornamental laurels pose a low risk from simple physical contact, several popular varieties contain potent toxins that are severely dangerous if ingested. Understanding the differences between these plants is necessary, as the chemical compounds involved can affect the body’s major systems. This article clarifies the specific toxic potential of the most common plants referred to as laurel.
Identifying the Different Laurel Types
The ambiguity surrounding the term “laurel” stems from its application to plants across multiple botanical families with vastly different chemical profiles. The three main groups are True Laurel, Toxic Laurels, and Toxic Stone Fruit Laurels. True Laurel, or Bay Laurel (Laurus nobilis), is generally considered safe and is the source of the culinary bay leaf, though its berries are mildly toxic.
Toxic Laurels include Mountain Laurel (Kalmia latifolia), an evergreen shrub native to North America. This plant is highly poisonous, as all parts contain neurotoxins known as grayanotoxins. The Toxic Stone Fruit Laurels include the common ornamental Cherry Laurel (Prunus laurocerasus), frequently used for hedging. This plant contains cyanogenic glycosides, a toxin that releases a potent poison upon digestion.
Toxicity Risks from Dermal Contact
For most people, simply touching the leaves or bark of common laurel varieties does not pose a serious acute health risk. The tough, waxy foliage of plants like Cherry Laurel and Bay Laurel does not readily transfer toxic compounds through intact skin. The primary concern from direct contact is typically mild skin irritation or an allergic reaction in sensitive individuals.
Skin contact with the sap, particularly when pruning or cutting the plant, is the main way dermal reactions occur. The sap of some ornamental laurels can cause contact dermatitis, resulting in a localized rash, redness, or itching. Mountain Laurel’s grayanotoxins are primarily a threat when eaten, meaning casual handling is generally safe unless the sap comes into contact with an open wound or mucous membranes.
Severe Danger from Ingestion
While touching laurel plants presents a low risk, the ingestion of leaves, bark, or berries from toxic varieties is severely dangerous and can be life-threatening. The specific danger depends on the type of laurel and the mechanism of its primary toxin.
Mountain Laurel’s toxicity is due to grayanotoxins, which target voltage-gated sodium channels in the body’s nerve and muscle cells. This interference causes prolonged depolarization, leading to overstimulation of the vagus nerve. Symptoms of this poisoning can manifest rapidly and include severe nausea, vomiting, dizziness, and excessive salivation, often followed by cardiac issues like a slow heart rate (bradycardia) and low blood pressure (hypotension).
The danger in Cherry Laurel and related stone fruit laurels comes from cyanogenic glycosides, such as prunasin and amygdalin. When plant material containing these compounds is chewed or digested, internal enzymes break them down to release hydrogen cyanide (HCN), a chemical asphyxiant. Cyanide prevents cells from using oxygen, effectively shutting down cellular respiration. Symptoms of severe poisoning include difficulty breathing, tremors, convulsions, and potentially cardiac arrest.
Safe Handling Procedures and First Aid
Adopting safety measures mitigates risks associated with laurel plants, especially during gardening and maintenance. When pruning or removing toxic laurel varieties like Cherry Laurel or Mountain Laurel, wearing protective equipment is recommended. Heavy-duty gardening gloves prevent sap and plant fragments from irritating the skin, and eye protection guards against accidental splashes of sap.
All tools, including secateurs and hedge trimmers, should be cleaned immediately after use. Plant cuttings should be disposed of properly, keeping them out of reach of children and pets. After any contact with the plant, hands and exposed skin should be thoroughly washed with soap and water.
In the event of known or suspected ingestion of any part of a toxic laurel, immediate action is necessary. Do not wait for symptoms to appear; contact a regional Poison Control Center or emergency services immediately for professional medical guidance.