Which plants cause GI toxicity (vomiting and diarrhea)?

• A. Rosary Pea and Precatory Beans (Abrus), Corn Cockle (Agrostemma), Deadly Amanita + Death Angel (Amanita), Mustards (Brassica), Autumn Crocus (Colchicum), Daphne (Daphne), Flowering Spurge + Poinsettia (Euphorbia), English Ivy (Hedera), Sneezeweed (Helenium), Christmas Rose (Helleborus), Hydrangea, Bitterweed (Hymenoxys), Holly (Ilex), Privet (Ligustrum), Daffodil + Jonquil (Narcissus), Mistletoe (Phoradendron), Pokeweed (Phytolacca), Mayapple + Mandrake (Podophyllum), Buttercup (Ranunculus), Marsh Marigold (Caltha), Castor Bean (Ricinus), Black Locust (Robinia), Soapweed + Bouncing Bet (Saponaria), Senna Bean + Rattlebox (Sesbania)
• B. Nettle and Stinging Nettles
• C. English Ivy and Sneezeweed
• D. Mustards (Brassica)

Answer: (A)

GI toxicity from plants comes from compounds that irritate or damage the lining of the gastrointestinal tract, leading to vomiting and diarrhea. The most reliable way to recognize plants that commonly produce this pattern of toxicity is to look for well-documented GI irritants and toxin-containing species. The long list in the correct option includes many classic sources of GI upset after ingestion, such as Abrus precatorius seeds (abrin), castor bean (ricin), corn cockle, autumn crocus (colchicine), deadly Amanita mushrooms, daphne, euphorbia latex–related irritants, English ivy, sneezeweed, hellebores, hydrangea, holly, narcissus, pokeweed, mayapple and mandrake, buttercup, marsh marigold, castor bean, privet, saponaria, and various Sesbania and Ranunculus species. Each of these has a recognized potential to cause vomiting and diarrhea through direct mucosal irritation or systemic toxin effects.

The other options list plants that are less consistently associated with GI-only toxicity or include only a few examples. That’s why the comprehensive set of GI irritants is the best answer—it captures the breadth of plants known to produce vomiting and diarrhea when ingested.