Is American Century Plant Poisonous? – Toxicity to Humans, Dogs, and Cats

The American century plant (Agave americana) deserves caution: its sap is a significant skin and mucous membrane irritant, and ingesting plant material causes gastrointestinal upset in both people and pets. It is not in the same danger category as plants containing cardiac glycosides, but it is not safe to handle carelessly or allow pets and children to chew.

What Makes the American Century Plant Toxic?

Several compounds in the plant can cause harm:

Calcium oxalate crystals are present in the sap and plant tissue. These microscopic needle-like crystals cause immediate mechanical irritation on contact with skin, eyes, or the lining of the mouth and digestive tract.

Saponins in the leaves and sap act as gastrointestinal irritants when ingested.

Furanocoumarins in the sap are phototoxic. When sap lands on skin and that skin is then exposed to sunlight or ultraviolet light, the result can be a chemical burn rather than ordinary irritation. This reaction can be delayed by hours and may catch people off guard.

The sharp terminal spine on each leaf tip also poses a puncture injury risk. Wounds from Agave spines can drive sap into tissue, intensifying the local reaction.

Toxic Parts

All parts of the plant carry some risk, but the sap is the main concern. Contact most commonly happens when:

• Leaves are broken or cut, releasing sap
• The plant is being pruned or transplanted
• A pet or child chews on a leaf

Symptoms

Dogs and cats: Drooling, pawing at the mouth, vomiting, and diarrhea after ingesting plant material. Skin contact with sap may cause localized irritation or redness. The taste and immediate mouth irritation usually discourage large ingestion.

Humans and children: Skin contact with sap can produce redness, swelling, and blistering, particularly if the exposed area is then in sunlight. Eye contact causes pain, tearing, and redness; sap in the eye should be treated promptly. Ingesting leaf material causes burning in the mouth and throat, nausea, vomiting, and abdominal discomfort.

The phototoxic burn from furanocoumarin exposure can appear hours after the initial sap contact, making the connection less obvious. Reactions vary by individual sensitivity and sun exposure.

What to Do

1. Remove any plant material from the mouth and rinse thoroughly with water.
2. Wash affected skin immediately with soap and water.
3. Flush eyes with clean water for at least 15 minutes if sap contact occurred.
4. Keep any skin that contacted sap out of sunlight for at least 24 to 48 hours to reduce phototoxic risk.
5. Call poison control at 1-800-222-1222 (US) or your vet if symptoms develop, persist, or if eye exposure occurred.
6. Do not induce vomiting unless directed by a medical professional.

Skin burns from phototoxic reactions may need medical treatment if blistering is significant.

Safe Handling

The American century plant is a popular landscape and container plant in dry climates. To reduce risk:

• Wear long sleeves, gloves, and eye protection when pruning or repotting.
• Wash tools and skin immediately after contact with sap.
• Avoid sun exposure on any skin that contacted sap for the rest of the day.
• Plant it away from paths, play areas, and pet runs. The leaf spines are a puncture hazard as well as a sap delivery mechanism.
• If you have young children or pets that chew plants, keep this plant in an inaccessible location.

Frequently Asked Questions

Is Agave americana the same plant used to make tequila? No. Tequila comes from Agave tequilana (blue agave). Agave americana is a related species but a different plant.

Are the flowers and seeds also toxic? The sap is present throughout the plant, including in flower stalks. Seeds are less commonly a problem but should not be ingested.

Can Agave burns be treated at home? Mild skin irritation from sap can be managed with washing and keeping the skin out of sunlight. Significant blistering or any eye contact warrants medical attention.

Is the American century plant safe for horses? Horses that graze on Agave can develop gastrointestinal upset from the saponins. Keep Agave out of pastures and paddock areas.