Daisies are cheerful, common garden flowers, but the term “daisy” refers to thousands of species within the large Asteraceae family. This vast plant family, also known as the composite family, includes familiar lawn and garden varieties, as well as plants like asters, sunflowers, and chrysanthemums. Because of this broad classification, assessing toxicity requires focusing on the most common types encountered by people.
Toxicity Status of Common Daisy Varieties
Common daisy varieties are considered to have low toxicity to humans. The risk is typically limited to mild digestive distress or skin irritation, rather than severe poisoning. The English Daisy (Bellis perennis), often seen in lawns, has been used in herbal remedies and is sometimes consumed in small quantities, such as in salads. However, consuming a large amount can cause gastrointestinal upset.
The Shasta Daisy (Leucanthemum × superbum), a popular garden hybrid, is also classified as mildly toxic. All parts of the plant, including the stems and leaves, contain sap with mild irritants. Minor ingestion by adults is not typically life-threatening, but it can cause adverse reactions. This mild toxicity means the plant is primarily a concern for young children or pets who might chew on the foliage.
The overall risk level from these common daisies is low. The toxins they contain are generally unpalatable, which naturally limits the amount a person or pet is likely to consume.
Chemical Compounds Behind Potential Reactions
The mild adverse effects associated with daisies stem from specific biological compounds, primarily sesquiterpene lactones (SLs). These compounds are common in Asteraceae plants and are responsible for both irritant and allergenic properties. Sesquiterpene lactones feature an alpha-methylene-gamma-lactone group within their chemical structure.
This molecular group is highly reactive due to its alkylating capabilities. The reaction occurs when the lactone binds to sulfhydryl groups found in proteins and in the antioxidant molecule glutathione within human cells. This binding process disrupts normal cellular function and can trigger an immune response.
When this reaction occurs on the skin, it initiates the inflammatory process known as allergic contact dermatitis. The interaction with skin cell proteins results in the characteristic redness, itching, and rash seen after handling certain daisy varieties. Upon ingestion, these irritating compounds affect the gastrointestinal tract lining, leading to stomach upset and nausea. The presence of pyrethrins, natural insecticides also found in some daisy varieties, can contribute to this mild irritation.
Recognizing Symptoms and Immediate Steps
Exposure to daisies results in two main types of symptoms: skin reactions and gastrointestinal distress. Contact with the plant sap or foliage can cause mild skin redness, a rash, or a form of allergic contact dermatitis in sensitive individuals. Symptoms typically appear as localized itching and inflammation where the skin touched the plant.
If a portion of the plant is ingested, symptoms are confined to the digestive system. These can include nausea, vomiting, diarrhea, and stomach cramps. Although unpleasant, these symptoms are usually self-limiting and resolve without aggressive treatment.
Immediate first aid for skin contact involves thoroughly washing the affected area with soap and water to remove residual sap or irritant compounds. For ingestion, rinse the mouth with water to clear any plant fragments. Offer small sips of water or milk to a conscious person who has swallowed part of the plant.
It is important to contact Poison Control immediately for guidance if any plant part has been swallowed, especially if the person is a small child or is experiencing severe symptoms. Seek emergency medical attention by calling 911 if there is difficulty breathing, swelling of the mouth or throat, or if the person becomes unresponsive. Do not attempt to induce vomiting unless specifically instructed to do so by a medical professional or the Poison Control Center.