Cherry Laurel, scientifically known as Prunus laurocerasus, is an evergreen shrub frequently planted in gardens and parks across the world. The plant contains potent chemical compounds that, when ingested, can lead to severe poisoning in both humans and animals. It is essential to recognize this common garden feature as a significant health hazard, especially in households with children or pets.
How Cherry Laurel Produces Cyanide
The toxicity of Cherry Laurel stems from the presence of natural defense chemicals called cyanogenic glycosides, such as prunasin and amygdalin, stored within its tissues. These glycosides are inherently harmless when the plant remains intact. However, the plant also harbors specific enzymes, like beta-glucosidase, kept separate from the glycosides in healthy cells.
When the plant material is damaged, such as by chewing, crushing, wilting, or digestion, the glycosides and enzymes mix. This contact initiates a chemical reaction known as hydrolysis, which rapidly breaks down the cyanogenic glycosides. The breakdown product is the highly poisonous gas, hydrogen cyanide (HCN), also known as prussic acid.
Hydrogen cyanide is a fast-acting poison because it interferes with cellular respiration. It binds to a specific enzyme in the cell’s mitochondria, cytochrome c oxidase, preventing the cells from utilizing oxygen for energy production. The release of this compound gives damaged cherry laurel a bitter almond-like odor.
Which Parts of the Plant Pose a Danger
All parts of the Prunus laurocerasus plant contain cyanogenic glycosides and are considered toxic. However, the concentration of the poisonous compounds varies significantly across different parts. The highest concentrations are found in the leaves, especially when they are wilted, and within the seeds or “pits” of the fruit.
The shiny, black fruit of the cherry laurel is generally less of a concern than the seeds inside. The fleshy pulp is low in the toxic compound, but the hard seed within contains high levels of cyanogenic glycosides. The risk escalates if the seed is chewed or crushed, which triggers the release of hydrogen cyanide.
The leaves are also a major source of exposure, especially for livestock and pets that may graze on fallen clippings or branches. Children may also be tempted to chew on the leaves or the somewhat sweet-tasting berries. Never use cherry laurel branches for cooking, skewers, or smoking food, as the wood and bark also contain the toxins.
Signs of Poisoning and Emergency Response
Symptoms of cyanide poisoning can manifest rapidly after ingestion. In humans, early signs can include abdominal pain, nausea, vomiting, dizziness, and headache. More severe effects quickly follow due to cellular oxygen deprivation, such as difficulty breathing, a rapid heart rate, and an unpleasant scratching sensation in the throat.
In pets like dogs and cats, initial signs may involve excessive drooling, mucosal irritation, and stomach issues. As the poisoning progresses, symptoms can escalate to muscle tremors, weakness, difficulty breathing, and a decline in coordination. In the most severe cases, convulsions, loss of consciousness, and respiratory paralysis can occur.
Immediate action is absolutely necessary if ingestion of any part of the cherry laurel is suspected. Do not attempt any home remedies like inducing vomiting, as this may delay professional medical intervention. The first and most important step is to call emergency services, such as Poison Control or an equivalent emergency line, and for pets, contact a veterinarian immediately.