Articles by Owen Dell
THE BIG TEN: Southern California Plants Seriously Poisonous to Humans by Owen E. Dell
Brugmansia sanguinea (Angel’s Trumpet)

Whole plant toxic, esp. seeds

Symptoms may appear in a few minutes or several hours

Thirst, dryness of mouth & skin, flushing of face, visual disturbances, nausea, rapid pulse, fever, delirium, incoherence,stupor

Victim may pick at imaginary objects in air or on body

Loss of memory

Children suck nectar from base of flower

Have been used deliberately for hallucinogenic effects

Ritualistic use among aboriginal peoples in South America

Conium maculatum (Poison Hemlock)

Distinguish by irregular purple spots on stems & petioles

Whole plant toxic, esp. roots, seeds

Similar to nicotine poisoning

Rapid onset of symptoms

Irritation of mouth & throat, salivation, nausea, vomiting, abdominal pain, diarrhea, thirst, headache, dilation of pupils, sweating, dizziness

Convulsions in severe cases, may cause death due to respiratory failure

Formerly used medicinally as anti-spasmodic, sedative, pain reliever

Common in So. Cal., esp. in riparian areas

May be mistaken for dill, parsley, anise.

Toxicity varies throughout the year

Most poisonous during growing season, flowering period

Dry material least toxic

Datura stramonium (Jimson Weed)

Whole plant toxic, seeds most often the culprit

Has been used deliberately to induce intoxication

Dry mouth, dilation of pupils, dry warm skin, reddening of face/neck, irregularheartbeat, delirium, hallucinations

Digitalis purpurea (Foxglove)

Whole plant toxic

Dried leaves are the source of the drug digitalis

Stimulation of heart, increased flow of urine, disturbed color vision

Can be fatal

Poisoning has occurred when leaves were mistaken for comfrey

Nerium oleander (Oleander)

Whole plant toxic

Smoke from burning wood toxic

Nausea, vomiting, dizziness, irregular heartbeat.

Can be fatal (Only 1 reported death, suspected suicide)

Children have become ill from sucking nectar from flowers

Reported deaths from using sticks to skewer meat are possibly apocryphal

Nicotiana glauca (Tree Tobacco)

Whole plant toxic, esp. leaves

Salivation, nausea, vomiting, diarrhea, clammy skin, palpitation

In severe cases, labored breathing, weak irregular pulse, faintness, collapse

Severely poisoned victim may die within a few minutes

Has caused several deaths in CA.

Seedlings appear edible

Respiratory paralysis may require use of iron lung

Ricinus communis (Castor Bean)

Seeds toxic, leaves to a lesser extent

Ricin is one of the most toxic compounds known

After several hours: burning of the mouth, nausea, vomiting, diarrhea, thirst, prostration, convulsions, circulatory collapse

May also cause contact dermatitis, pollen allergies

Number of seeds to produce illness/death varies

2-3 can be fatal to children

2-4 can be fatal to adults

Castor oil is obtained from seeds is not poisonous, though cathartic

Plant reduces population of nematodes in soil

Seed coat must be broken or chewed to release toxin

Taxus baccata (English Yew)

Entire plant toxic, esp. seeds

Highly toxic

Causes gastrointestinal irritation, dizziness, dry throat, dilation of pupils, abdominal pain, nausea, vomiting.

Muscular weakness, rash on skin, comatose, irregular heartbeat

Sudden death can occur of large amounts are ingested

Sonoma Co., March 1969

5 ewes, 1 lamb died

Ewes killed by Yews

Toxicodendron diversilobum (Poison Oak)

Entire plant toxic, exc. pollen

Toxic all year, including winter

Sensitization occurs after first contact, symptoms appear on subsequent contacts

Time to develop symptoms can be as little as 24 hours in highly sensitive persons

Redness, swelling of skin, constant itching, then blisters

Very sensitive persons may experience swelling of eyes, throat, stomach cramps,nausea, vomiting, diarrhea

Toxin carried in smoke

Lasts 10 days or less

Calamine lotion, cold compresses, cortisone in extreme cases

avoid oily or alcohol-based solutions, benzocaine, phenol, camphor, iron, zirconium


many kinds

difficult to identify

Kinds of toxins

Causing cellular destruction, kidney and liver damage

Symptoms do not appear for up to 12 hrs.

May be fatal


Amanita poisoning causes 90% of fatal cases of mushroom poisoning


Affecting autonomic nervous system

Symptoms appear within 15 minutes to 6 hours

Affecting central nervous system

Symptoms appear within 20 minutes to 2 hours

Includes hallucinogenic mushrooms

Causing gastrointestinal irritation

Largest number of toxic mushrooms are in this group

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