Plants have evolved highly complex systems of defense against most of their natural enemies (eg, insects, animals). At the very least, these defenses make many plants unpalatable; however, some can be fatal to the inexperienced forager.
Resins represent one form of plant defense. See the image below.
Hemlock. Photo by Cornell University Poisonous Plants Informational Database.
Throughout human history, plants have played pivotal roles as medicines and poisons. Our medical predecessors may not have known the exact mechanisms involved, but they did recognize various plants as instrumental for medical treatment and as instruments of murder. With current technology, we finally are able to peer into plants and see their vast arsenal of chemicals, including glycosides, alkaloids, oxalates, and resins.
A rapid toxidromic classification of plant poisonings has been developed for use by first responders and other urgent-healthcare providers to assist in rapid identification of poisonous plant–induced toxidromes and to reduce confusion among highly toxic, less toxic, and nontoxic plants. The resultant 4 specific toxidromes of plant poisonings identified in the scientific literature are stratified as cardiotoxic, neurotoxic, cytotoxic, and gastrointestinal/hepatotoxic poisonings, all of which have caused fatalities worldwide after both intentional and unintentional ingestions.
When considering poisoning by plant resin, always be aware of possible co-intoxicants, which may blur the clinical picture. Such co-intoxicants include pharmaceutical and illicit drugs, herbicides, fungicides, insecticides, fertilizers, and artificial plant hormones.
Examples of unintentional toxic plant ingestion include the following:
Hikers who mistake poisonous plants for nutritious ones
Herbalists who seek natural remedies or natural highs and end up with poisonous concoctions
Children who are attracted to brightly colored fruits and leaves of poisonous plants (this group accounts for the most calls to poison centers regarding plant toxicity)
See 11 Common Plants That Can Cause Dangerous Poisonings, a Critical Images slideshow, to help identify plant reactions and poisonings. For patient education information, see the First Aid and Injuries Center, as well as Poisoning and Activated Charcoal.