Hyssop loosestrife Toxic?

Updated 2026-03-06| 4 min read| 936 found this helpful

All parts of the plant are highly toxic, with suspected active compounds including tannins and their phenolic metabolites.

Ingestion causes liver/kidney failure in sheep and cattle 2-14 days post-consumption, with mortality rates up to 33% in cows.

No specific antidote exists; treatment relies on symptomatic veterinary care and immediate removal of contaminated feed.

FAQ

Is Hyssop loosestrife toxic to Humans?

No confirmed human toxicity data is available; seek immediate medical attention if ingestion is suspected. (Low)

Is Hyssop loosestrife toxic to Cats?

No confirmed feline toxicity data is available; consult a veterinarian immediately if ingestion is suspected. (Low)

Is Hyssop loosestrife toxic to Dogs?

No confirmed canine toxicity data is available; consult a veterinarian immediately if ingestion is suspected. (Low)

Is Hyssop loosestrife toxic to Horses?

No confirmed equine toxicity data is available; consult a veterinarian immediately if ingestion is suspected. (Low)

Not sure which plant? Snap a photo to ID in 1 secondGet App

Toxicity Details

Humans

Low

No confirmed human toxicity data is available; seek immediate medical attention if ingestion is suspected.

Cats

Low

No confirmed feline toxicity data is available; consult a veterinarian immediately if ingestion is suspected.

Dogs

Low

No confirmed canine toxicity data is available; consult a veterinarian immediately if ingestion is suspected.

Horses

Low

No confirmed equine toxicity data is available; consult a veterinarian immediately if ingestion is suspected.

Toxicity Snapshot

Toxic PartsWhole plant

Exposure RouteIngestion is the only confirmed toxic exposure route; no contact toxicity has been documented.

Toxic CompoundsUnknown; Phenols (tannins and their metabolites, suspected)

First Aid & Prevention

First 30 Minutes

• Immediately remove all remaining plant material from the exposed individual/animal's access
• Collect a sample of the ingested plant for formal identification
• Do not induce vomiting or administer home remedies unless explicitly directed by a medical/veterinary professional

Contact Vet Immediately

• Observed or suspected ingestion of the plant
• Appearance of symptoms including lethargy, loss of appetite, jaundice, difficulty urinating, or poor coordination
• Abnormal blood work results indicating elevated liver or kidney values after potential exposure

Prevention

• Regularly inspect livestock pastures, hay, and forage for contamination with Hyssop loosestrife
• Remove all identified plants from areas accessible to grazing animals
• Avoid feeding any forage or hay known to contain this plant to livestock

Treatment & Prognosis

• Administer symptomatic supportive care as directed by a veterinarian
• Immediately change any feed confirmed to be contaminated with the plant
• Monitor liver and kidney function via regular blood work for at least 2 weeks post-exposure

Emergency? Open PlantFun for real-time AI guidanceGet App

Professional Toxicology

Scientific NameLythrum hyssopifolia L.

AliasesLesser loosestrife、Grass-poly、Ysopblättriger Weiderich、Ysop-Blutweiderich、Salicaire à feuilles d'hysope、Salcerella con foglie d'issopo

Toxicity Grade

HumansLow

CatsLow

DogsLow

HorsesLow

Target Organs

LiverKidneysSkin (photosensitivity reactions)

Mechanism of Action

• Suspected toxic tannin metabolites cause progressive oxidative damage to liver and kidney tissue

• Toxic effects develop gradually over 2 to 14 days after ingestion in susceptible ruminant species

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Cattle: Ingestion leads to liver and/or kidney failure 2-14 days post-exposure; symptoms include lethargy, jaundice, photosensitivity, and dysuria, with mortality rates of 6.7-33%.

Sheep: Ingestion leads to liver and/or kidney failure 2-14 days post-exposure; symptoms include ataxia, anorexia, and elevated blood urea/creatinine levels, with mortality rates of 1-20%.

Confusion Risk

The following plants look similar and may be confused:

Other Lythrum species Lythrum spp.

Many other Lythrum species are non-toxic, making visual differentiation difficult; confirm identity via leaf morphology and flower color if exposure is suspected

Use PlantFun to scan and avoid misidentificationGet App

Related Toxic Plants

Purple Loosestrife

Lythrum salicaria

Low (mild gastrointestinal irritation if ingested in large quantities)

Henna Tree

Lawsonia inermis

Moderate (causes hemolytic anemia in dogs, cats, and horses)

Giant Crape Myrtle

Lagerstroemia speciosa

Low (mild gastrointestinal upset if large amounts are consumed)

Download PlantFun App

Identify, grow and care for plants effectively!

Instant Plant ID

Take a photo to quickly identify plants.

Smart Care Reminders

Generate watering and care schedules.

Toxicity & Disease Diagnosis

Identify toxic plants and pests with treatment advice.

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.