Numerous plant parts and products have been implicated in contact dermatitis. Symptoms often vary and depend on several factors including the sensitivity of the individual, the extent of contact, and the condition of the plant or plant product.

Contact dermatitis is an itchy rash caused by direct contact with a substance or an allergic reaction to it. The rash isn't contagious, but it can be very uncomfortable. Many substances can cause this reaction, such as cosmetics, fragrances, jewelry and plants. The rash often shows up within days of exposure.

The following list covers many of the plants most frequently associated with dermatitis, but it is not all-inclusive:

Ailanthus altissima aka Tree of Heaven

Anacardium occidentale aka Cashew nut

Anagallis arvensis aka Scarlet pimpernel

Anthemis arvensis aka Corn chamomile

Anthemis cotula aka Dog fennel

Aralia spinosa aka Hercules club

Arctium lappa aka Great burdock

Arisaema triphyllum aka Jack-in-the-pulpit

Asarum canadense aka Wild ginger

Asimina triloba aka Papaw

Asparagus officinalis aka Asparagus

Borago officinalis aka Borage

Buxus sempervirens aka Boxwood

Cannabis sativa aka Hemp, Marijuana

Catalpa speciosa aka Catalpa

Caulophyllum thalictroides aka Blue cohosh

Chelidonium majus aka Celandine

Chimaphila umbellate aka Pipsissewa

Clematis virginiana aka Virgin’s bower

Colchicum autumnale aka Autumn crocus

Conium maculatum aka Poison-hemlock

Convallaria majalis aka Lily of the valley

Cypripedium reginae aka Showy lady-slipper

Cypripedium parviflorum aka Yellow lady-slipper

Daphne mezereum aka Daphne

Datura stramonium aka Jimson-weed

Daucus carota aka Wild carrot

Delphinium ajacis aka Larkspur

Dictamnus albus aka Gasplant, Dittany

Dirca palustris aka Leatherwood

Echium vulgare aka Vipers bugloss

Encelia californica aka California encelia

Erigeron canadensis aka Horseweed

Euphorbia marginata aka Snow-on-the-mountain

Euphorbia spp. aka Spurge

Fagopyrum esculentum aka Buckwheat

Gelsemium sempervirens aka Yellow Jessamine

Ginkgo biloba aka Gingko, Maidenhair-tree

Hedera helix aka English ivy

Helleborus niger aka Christmas-rose

Heracleum lanatum aka Cow-parsnip

Hippomane mancinella aka Manchineel

Humulus lupulus aka Hops

Hypericum perforatum aka St. Johns-wort

Iris versicolor aka Blue flag

Iris spp. aka Iris

Iva xanthifolia aka Marsh-elder

Jatropha stimulosa aka Spurge nettle

Juniperus virginiana aka Eastern red cedar

Juniperus spp. aka Juniper

Laportea canadensis aka Wood nettle

Leonurus cardiaca aka Motherwort

Lobelia inflate aka Indian tobacco

Lycopersicon esculentum aka Tomato

Maclura pomifera aka Osage-orange

Mentzelia spp. aka Mentzelia

Metopium toxiferum aka Poison-wood

Nerium oleander aka Oleander

Pastinaca sativa aka Wild parsnip

Phaecelia spp. aka Phacelia

Podophyllum peltatum aka May-apple

Polygonum spp. aka Smartweed

Primula spp. aka Primrose

Ptelea trifoliate aka Wafer ash or Hoptree

Ranunculus spp. aka Buttercups

Rheum rhaponticum aka Rhubarb

Rhus verniciflua aka Japanese varnish-tree

Rumex spp. aka Sorrel, Dock

Ruta graveolens aka Rue

Sanguinaria canadensis aka Bloodroot

Sedum acre aka Mossy stonecrop

Toxicodendron radicans aka Poison ivy, Poison oak

Toxicodendron vernix aka Poison sumac

Trifolium hybridum aka Alsike clover

Urtica spp. aka Nettles

Veratrum viride aka False hellebore

List compiled from the following sources:
Muenscher, W.C. 1960. Poisonous Plants of the United States. The Macmillan Company, New York, NY, 227 pp.
Tampion, J. 1977. Dangerous Plants. Universe Books, New York, NY, 176 pp. 

Summary

This fact sheet is a compilation of plants that have been reported to cause contact dermatitis in humans. Plants are listed by both their common and Latin names.