Poisonous Plants in Arizona and the Southwest

The Southwest’s diverse landscape boasts many beautiful plants. However, not all are safe to touch or ingest (eat). This guide highlights some common plants found throughout Arizona and the Southwest with varying levels of toxicity (or harmfulness).

Know the degrees of toxicity

"Poisonous" plants can have different toxicity levels. Some parts, like seeds in castor beans, are the most dangerous. Others, like oleander leaves, are toxic throughout the plant.

Here are some potential complications or side effects of touching or ingesting the local plant life.

Cardiac complications: Eating of any part of the Arizona desert foxglove, yellow and white oleander and Arizona milkweed can disrupt your heart rhythm and cause nausea, vomiting, vision problems and even death. Interestingly, the potentially harmful compounds found in these species are also used in the medication digoxin to help treat irregular heart rhythms and congestive heart failure, but only in precise, controlled doses.

Local irritants: Ingestion of dumbcane, philodendron, elephant’s ear, peace lily, and pothos leaves can cause a burning sensation and swelling in the mouth but typically have no systemic effects.

Dangerous hallucinations: Eating the seeds from the Jimsonweed plant or any portion of Angel’s trumpet are hallucinogenic and abused by some, but the hallucinations are unpredictable and dangerous. Ingestion can also lead to rapid heart rate, fever, confusion and urinary problems.

Unpredictable toxins: Eating the seeds from the Texas mountain laurel tree usually causes salivation, nausea and vomiting. The harmful compound from the seeds is similar to nicotine and can also produce severe side effects resulting in elevated heart rate, depressed blood pressure, seizures and in rare cases, even death if ingested in large amounts.

Another native Arizona plant with a poison similar to nicotine is poison hemlock which can be mistaken for wild carrot, parsley or fennel. It can cause serious toxicity if even a very small part (any part) of the plant is ingested. Symptoms begin with a stimulant effect, nausea, vomiting and confusion followed quickly by coma and muscle paralysis.

Ingestion of the seeds from the castor bean plant can also be very harmful, even in small quantities. Ricin, which is found in the castor bean stops your body from producing essential proteins your individual cells and body need (protein synthesis) causing severe nausea, vomiting and fever. It can even lead to a coma and potentially death from liver and kidney failure.

Common culprits: In small quantities, ingestion of any part of the candelabra cactus, aloe vera, lantana and mistletoe plants typically cause nausea and diarrhea. Lantana can also cause skin blisters after a skin exposure to the sap.

Eye irritant: The most common plant involved in poison center-related calls involves pencil cactus (or firestick plants). Not a true cactus, and in the succulent family, exposure to the sap from this plant can cause significant irritation to both your skin and eyes. It can cause a strong painful burning sensation in your eyes, most often from rubbing your eyes with sap residue left on your hands while working with the plant.

Neurologic toxins: Even relatively small ingestion of the yellow jasmine can produce symptoms like nausea, vomiting, dizziness, weakness and blurred vision. Although rare, eating larger amounts of this plant can also result in seizures.

The itch factor: You may have heard "leaves of three, let it be!" Poison oak and poison ivy cause a distinctive blistering, itchy rash, irritation and pain wherever skin contacts the plant's oil.

Safety first

While Arizona has many non-toxic plants, you should never eat wild plants unless you can positively identify them as safe. Remember, most accidental poisonings cause minimal harm.

Identify before you hike

For photos and information on common Arizona plants, visit the Arizona Native Plant Society website. 

For more information or if you think you’ve touched or ingested a potentially poisonous plant, call your local poison control center available 24/7 at (800) 222-1222.