Is Coyotilla Poisonous? – Toxic Berries and Delayed Paralysis Risk

Coyotilla (Karwinskia humboldtiana, also called tullidora or coyotillo) is seriously toxic to humans, dogs, and livestock. The plant’s berries contain anthracenone toxins that damage the nervous system, producing a delayed, progressive paralysis of the limbs. Symptoms may not appear until two to four weeks after ingestion, which means exposure is often not connected to the plant by the time a person or animal becomes ill.

What Part of Coyotilla Is Toxic?

The seeds are the most concentrated source of toxins, but all parts of the plant carry risk. The primary toxic compounds are anthracenones including T-514, also called peroxisomicine A1. These compounds cause demyelination and axonal degeneration in the peripheral nervous system, which leads to the characteristic ascending paralysis.

The plant grows as a shrub or small tree across northern Mexico, the southwestern United States (Texas, New Mexico, and Arizona), Central America, and parts of the Caribbean. The berries have a sweet taste, which increases the chance of accidental ingestion by children and animals.

Symptoms of Coyotilla Ingestion

The most distinctive and dangerous feature of coyotilla poisoning is its delayed onset.

Dogs and livestock: Progressive ascending flaccid paralysis starting in the hind limbs. Animals may appear completely normal for weeks before suddenly losing the ability to use their back legs. The paralysis advances toward the forelimbs. Involvement of respiratory muscles can be fatal.

Humans and children: The pattern is the same: a delay of two to four weeks, followed by progressive, symmetrical flaccid paralysis of the limbs starting from the feet. Eating small amounts repeatedly over time produces the same outcome as a single larger exposure. Severe cases progress to quadriplegia, difficulty swallowing, and respiratory failure. The clinical presentation resembles Guillain-Barre syndrome.

What to Do If Someone Ingests Coyotilla

1. If ingestion is known or suspected, seek medical or veterinary attention immediately, even before any symptoms appear.
2. Do not wait for paralysis to develop. By the time limb weakness begins, significant nerve damage has already occurred.
3. Call poison control at 1-800-222-1222 (US) and describe the plant and the approximate amount consumed.
4. For pets, contact your vet and the ASPCA Animal Poison Control Center at 888-426-4435.
5. Tell doctors or vets that coyotilla toxicity has a delayed onset, so appropriate monitoring can begin right away.

There is no specific antidote. Treatment is supportive. Early identification is the best available advantage.

Safe Handling

• If coyotilla grows on or near your property in the southwestern United States or Mexico, remove the plant or fence off the area to protect children and animals.
• The berries can appear appealing to children because of their sweet taste. Teach children not to eat wild berries they cannot identify.
• Wear gloves when handling the plant.
• Learn to identify the plant in your region: it is a shrub with small, dark berries and simple oval leaves, native to dry and semi-arid areas.

Frequently Asked Questions

Where does coyotilla grow? It is native to northern Mexico and extends into Texas, New Mexico, and Arizona. It also grows in Central America and parts of the Caribbean. It is not grown as a houseplant.

Can coyotilla cause permanent damage? Yes. Severe cases can result in permanent neurological damage or death. Early intervention before symptoms develop offers the best chance of recovery.

Is coyotilla the same as common buckthorn? No. Karwinskia humboldtiana is sometimes called buckthorn as a regional common name but is unrelated to other plants known as buckthorn (Rhamnus or Frangula species).

Why does paralysis take weeks to appear? The anthracenone toxins cause nerve damage that accumulates before clinical signs emerge. The gap between ingestion and symptoms is a key reason coyotilla poisoning often goes unrecognized until the paralysis is already advanced.