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Toxic☠️ To avoid

🍂 Poison ivy

Toxicodendron radicans · Anacardiaceae

🍁 North America
🧠 To remember it“Leaves of three, let it be” — three shiny leaflets, never touch it.
Poison ivy — Toxicodendron radicans

🔍 Identify it without mistakes

Extremely common climbing or bushy plant in North America, responsible for the continent's most frequent contact dermatitis. You can spot it by its compound leaf with three shiny leaflets — hence the North American saying "leaves of three, let it be" — and its resinous oil, urushiol, triggers a severe allergic reaction at the slightest contact, even years after touching a contaminated tool or piece of clothing.

  1. compound leaf with 3 shiny leaflets, the central leaflet attached by a small petiole longer than the two side ones
  2. variable leaflet edges: smooth, toothed, or lobed depending on the individual plant
  3. foliage turns a dramatic bright red in autumn
  4. variable growth habit: climbing vine with aerial roots, low shrub, or ground cover depending on the environment
Sizeclimbing vine up to 10 m or shrub from 30 cm to 1 m
FloweringMay-June, small greenish-white berries in autumn
Habitatforest edges, trail sides, hedgerows, waste ground throughout temperate North America

⚠️ Not to be confused with

Virginia creeper (5 leaflets, edible... not eaten, but safe to touch) (Parthenocissus quinquefolia)no danger of contact with Virginia creeper

To tell them apart: Virginia creeper has 5 leaflets arranged like a fan, while poison ivy only has 3 — the saying "leaves of three, let it be" targets this exact difference

Staghorn sumac (genus confusion) (Rhus typhina)none for staghorn sumac

To tell them apart: staghorn sumac has compound leaves with many elongated leaflets arranged like a comb and upright, velvety red fruit cones, very different from poison ivy's 3 simple leaflets

☠️ What kills

nomUrushiol (a mixture of allergenic catechols), present throughout the entire plant including the roots and dead wood
dose letale estimeenon-lethal through standard skin contact; however, inhaling smoke from burning the plant can cause potentially fatal pulmonary edema, and a severe generalized anaphylactic reaction remains possible in highly sensitized individuals (approx)
delai12 to 48 hours after contact for the skin rash to appear; a few minutes to a few hours for respiratory distress if smoke is inhaled
symptomesredness, intense itching, oozing blisters in lines or patches where skin touched the plant; if smoke is inhaled: coughing, breathing difficulty, airway swelling that may require hospitalization
antidoteno antidote; symptomatic treatment (antihistamines, topical or systemic corticosteroids depending on severity)
morts documenteesrare but documented, almost exclusively from smoke inhalation when burning the plant (wildland firefighters in particular) causing severe pulmonary edema

First steps : Immediately wash exposed skin with cold water and soap (ideally within 10 minutes, as urushiol penetrates quickly). Never burn the plant or go near a fire where it might be burning — call emergency services if you cough or experience breathing distress after possible smoke inhalation. Wash all clothing and tools that came into contact separately.

Sources (3)

No entry replaces a certain identification in the field, or medical advice. When in doubt: don't eat it. If ingestion is suspected: poison control or 112/911.