Cow Parsley (Anthriscus sylvestris) is a common member of the Apiaceae family, often seen blooming along roadsides and hedgerows. This family includes familiar vegetables like carrots, but also contains dangerously toxic plants. Concern about touching Cow Parsley stems from its close visual resemblance to these toxic relatives, which can cause severe skin reactions or be fatal if ingested. This article addresses the direct risk posed by Anthriscus sylvestris upon contact and details how to distinguish it from poisonous look-alikes.
Is Cow Parsley Dangerous to Touch
Cow Parsley (Anthriscus sylvestris) is generally considered non-phototoxic and poses minimal risk of severe skin irritation upon simple contact. Unlike its more dangerous relatives, the sap does not contain high enough concentrations of phototoxic chemicals to cause the blistering rashes associated with plants like Giant Hogweed. Brushing past the plant in a field or hedgerow is unlikely to result in any noticeable skin reaction for most people.
The Apiaceae family produces furocoumarins, compounds that sensitize human skin to ultraviolet light, causing a condition called phytophotodermatitis. While Cow Parsley may contain trace amounts of these compounds, its levels are significantly lower than those found in plants like wild parsnip or Giant Hogweed. The primary danger in handling Cow Parsley is the high risk of confusing it with a far more toxic species. Mild skin irritation can still occur in sensitive individuals, so cautious handling of any wild plant is always advised.
Identifying Highly Toxic Look-Alikes
The greatest risk associated with Cow Parsley is misidentification with dangerous plants sharing the umbrella-shaped flower structure. Two highly toxic look-alikes are Giant Hogweed (Heracleum mantegazzianum) and Poison Hemlock (Conium maculatum), which cause serious harm through contact or ingestion.
Giant Hogweed
Giant Hogweed is notably larger than Cow Parsley, often reaching heights of 8 to 14 feet, with flower heads spanning up to two feet across. Its stem is green, featuring distinct, coarse, rigid hairs and prominent purple or reddish-purple blotches. Contact with the clear sap is highly dangerous, causing severe phytophotodermatitis. This leads to painful, burning blisters and potentially long-lasting scars when exposed to sunlight.
Poison Hemlock
Poison Hemlock is deadly, known for its internal toxicity due to poisonous pyridine alkaloids like coniine. Its stem is smooth, entirely hairless, and hollow, featuring extensive purple blotches and spots. When crushed, the leaves or stems emit a distinct, unpleasant, musty, or “mousy” odor, unlike the fresh, slightly carroty scent of Cow Parsley.
Cow Parsley is much smaller, generally growing to a maximum of four feet tall. Its stems are delicate, grooved, and covered in fine, velvety hairs, especially toward the base. Any purple coloration on a Cow Parsley stem is typically a uniform “wash” rather than the distinct, splotchy blotches seen on Poison Hemlock. The leaves are fern-like and bright green, lacking the silvery sheen often noted on Poison Hemlock leaves.
Action Steps Following Potential Exposure
If contact is made with a suspected phototoxic plant (like Giant Hogweed or Poison Hemlock), immediate action is necessary to minimize the risk of a reaction. The first step is to thoroughly wash the affected skin area with copious amounts of soap and water as quickly as possible. Gently scrub underneath the fingernails with a brush to ensure any residual sap is removed, preventing the spread of toxins to other parts of the body.
After cleaning, the skin must be protected from sunlight for at least 48 hours, as UV light activates the phototoxic compounds in the sap. Covering the area with clothing is essential, and staying indoors during peak daylight hours is advisable if the contamination is widespread. If a severe burning sensation or blistering begins, the affected area should be treated like a thermal burn by gently cleaning it with cool water and applying a cold compress.
For less severe reactions, such as mild itching or localized redness, over-the-counter treatments can be used. Applying calamine lotion or a mild hydrocortisone cream helps soothe irritation and reduce inflammation. An oral antihistamine may also be taken to help manage swelling or widespread itchiness.
Professional medical attention is required immediately if severe symptoms develop. These include extensive blistering over a large area, swelling of the face or genitals, or difficulty breathing. Eye contact with the sap of plants like Giant Hogweed requires prompt emergency medical care, as this can result in temporary or permanent vision impairment. If ingestion of a toxic look-alike is suspected, contact a poison control center immediately.