Monk's-rhubarb Toxic?

Updated 2026-03-06| 3 min read| 1,014 found this helpful

All plant parts are toxic, including when processed into dry fodder, containing oxalates, anthracene derivatives, and other harmful compounds

Sheep and horses are highly sensitive to its toxins, while cattle can develop partial tolerance after slow, continuous low-level exposure

Severe ingestion can cause heart arrhythmia, kidney damage, paralysis, and potentially fatal outcomes in sensitive species

FAQ

Is Monk's-rhubarb toxic to Humans?

Potential vomiting, bloody diarrhea, colic, abnormal heart rhythm, tremors, blood in urine, or kidney damage if ingested in large amounts (Low)

Is Monk's-rhubarb toxic to Cats?

No species-specific data available; expected symptoms include vomiting, diarrhea, abdominal pain, and kidney irritation following ingestion (Low)

Is Monk's-rhubarb toxic to Dogs?

No species-specific data available; common expected symptoms are vomiting, diarrhea, abdominal discomfort, and possible kidney damage after ingestion (Low)

Is Monk's-rhubarb toxic to Horses?

Colic, abnormal heart rhythm, hypotension, tremors, paralysis, blood in urine, anemia, cachexia, and potentially fatal outcomes; horses have high sensitivity to oxalate toxins (Low)

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Toxicity Details

Humans

Low

Potential vomiting, bloody diarrhea, colic, abnormal heart rhythm, tremors, blood in urine, or kidney damage if ingested in large amounts

Cats

Low

No species-specific data available; expected symptoms include vomiting, diarrhea, abdominal pain, and kidney irritation following ingestion

Dogs

Low

No species-specific data available; common expected symptoms are vomiting, diarrhea, abdominal discomfort, and possible kidney damage after ingestion

Horses

Low

Colic, abnormal heart rhythm, hypotension, tremors, paralysis, blood in urine, anemia, cachexia, and potentially fatal outcomes; horses have high sensitivity to oxalate toxins

Toxicity Snapshot

Toxic PartsEntire plant; young tender leaves are sometimes consumed as wild vegetable in small, cooked preparations

Exposure RouteOral ingestion is the primary exposure route; no documented dermal or inhalation toxicity

Toxic CompoundsPotassium oxalate (content 2-10%); Free oxalic acid (1% in leaves); Physcion; Chrysophanol; Emodin; Nepodin; Neposid; Prientalon; Tannins; Potentially accumulated nitrates

First Aid & Prevention

First 30 Minutes

• Induce vomiting only if ingestion occurred within the last 15 minutes and the affected individual is fully conscious
• Administer oral calcium supplements (e.g. calcium gluconate) if available to precipitate toxic oxalates
• Avoid giving any acidic foods or drinks that may increase oxalate absorption

Contact Vet Immediately

• If any symptoms like vomiting, bloody diarrhea, colic, tremors, or abnormal urine output appear after ingestion
• If a horse, sheep, or other large livestock ingested any quantity of the plant
• If a child or pet ingested more than a small bite of the plant

Prevention

• Avoid allowing livestock (especially horses and sheep) to graze in areas with heavy growth of this plant
• Do not confuse this plant with edible rhubarb or spinach when foraging for wild vegetables
• Ensure dry fodder is free of contamination with this plant, as it remains toxic when dried

Treatment & Prognosis

• Administer calcium via gastric tube to precipitate ingested oxalates
• Perform decontamination procedures (e.g. activated charcoal administration) as appropriate
• Provide symptomatic and supportive care including pain relief, fluid therapy to support kidney function, and antihistamines if needed

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Professional Toxicology

Scientific NameRumex alpinus L.

AliasesMunk's rhubarb、Alpine dock、Alpen-Ampfer、Alpen-Mönchsrhabarber、Rumex des Alpes、Oseille des Alpes、Romice alpino、Rabarbaro alpino

Toxicity Grade

HumansLow

CatsLow

DogsLow

HorsesLow

Target Organs

Gastrointestinal tractKidneysCardiovascular systemNervous systemBlood cells

Mechanism of Action

• Oxalates bind to calcium in the body, leading to hypocalcemia and formation of sharp calcium oxalate crystals that damage soft tissues and kidney tubules

• Anthracene and naphthalene derivatives have irritant and systemic toxic effects on the gastrointestinal tract, nervous system, and cardiovascular system

• Accumulated nitrates can cause additional oxygen transport impairment in cases of large ingestion

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Sheep: Very high sensitivity; symptoms include depression, salivation, tremor, ataxia, recumbency, dyspnea, vomiting, and high risk of fatal aspiration pneumonia

Cattle: Can develop partial tolerance to oxalates with slow continuous exposure, as oxalate-degrading microbes proliferate in the rumen

Goats: No species-specific data available, expected sensitivity similar to sheep

Confusion Risk

The following plants look similar and may be confused:

Common sorrel Rumex acetosa

Closely related Rumex species with overlapping habitats; both have large broad leaves, but common sorrel is smaller with more distinctly arrow-shaped leaves

Curly dock Rumex crispus

Widespread related Rumex species; it has distinctly wavy, curled leaf edges, unlike the smoother, broader leaves of Monk's-rhubarb

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Related Toxic Plants

Garden rhubarb

Rheum rhabarbarum

Moderate toxicity (leaves are toxic, stems are edible when cooked)

Japanese knotweed

Fallopia japonica

Moderate toxicity, causes gastrointestinal irritation and allergic reactions

Wild buckwheat

Fagopyrum esculentum

Low to moderate toxicity, causes photosensitization in grazing livestock

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Data Sources

1. CliniTox (Universität Zürich)

This information is for reference only and does not constitute medical advice. If ingestion or poisoning is suspected, seek medical or veterinary attention immediately.