White Heads Toxic?

Updated 2026-03-06| 2 min read| 3,167 found this helpful

Sphenosciadium capitellatum

White Heads is confirmed toxic to cats, dogs, and horses per official ASPCA records

Its primary toxic active compound is furanocoumarins that trigger phototoxic reactions

Exposure leads to symptoms including photosensitive dermatitis and ocular damage

FAQ

Is White Heads toxic to Humans?

No confirmed human toxicity data available; avoid skin contact and ingestion as a precaution (Low)

Is White Heads toxic to Cats?

Photosensitization leading to ulcerative, exudative dermatitis, plus ocular toxicity (Moderate)

Is White Heads toxic to Dogs?

Photosensitization leading to ulcerative, exudative dermatitis, plus ocular toxicity (Moderate)

Is White Heads toxic to Horses?

Photosensitization leading to ulcerative, exudative dermatitis, plus ocular toxicity (Moderate)

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

Toxicity Details

Humans

Low

No confirmed human toxicity data available; avoid skin contact and ingestion as a precaution

Cats

Moderate

Photosensitization leading to ulcerative, exudative dermatitis, plus ocular toxicity

Dogs

Moderate

Photosensitization leading to ulcerative, exudative dermatitis, plus ocular toxicity

Horses

Moderate

Photosensitization leading to ulcerative, exudative dermatitis, plus ocular toxicity

Toxicity Snapshot

Toxic PartsAll above-ground plant parts, particularly leaves and sap, are confirmed to contain toxic compounds

Exposure RouteDirect skin contact with sap, ingestion of plant material, followed by exposure to UV light to trigger symptoms

Toxic CompoundsFuranocoumarins

First Aid & Prevention

First 30 Minutes

• Move the exposed animal to a fully shaded area immediately to prevent UV worsening symptoms
• Rinse all skin and eye contact areas thoroughly with cool clean water for 10+ minutes
• Remove any remaining plant material from the animal's mouth, fur, or paws if recently exposed

Contact Vet Immediately

• You observe redness, blistering, oozing skin or eye irritation after plant exposure
• The animal has ingested any quantity of Sphenosciadium capitellatum
• Symptoms persist or worsen after completing initial first aid steps

Prevention

• Restrict cat, dog, and horse access to areas where this plant grows wild
• Wear protective gloves and clothing when handling the plant to avoid skin contact
• Remove the plant from pet-accessible yards, pastures and recreational areas if present

Treatment & Prognosis

• Veterinary administration of anti-inflammatory medications to reduce dermatitis and eye irritation
• Topical ocular medications to treat eye tissue damage if present
• Keep affected animals out of direct sunlight for 1-2 weeks until photosensitivity resolves

Emergency? Open PlantFun for real-time AI guidanceGet App

Professional Toxicology

Scientific NameSphenosciadium capitellatum

AliasesRanger's Button

Toxicity Grade

HumansLow

CatsModerate

DogsModerate

HorsesModerate

Target Organs

SkinEyes

Mechanism of Action

• Furanocoumarins absorb UV radiation after skin contact or ingestion, triggering phototoxic reactions

• UV-activated compounds cause cellular damage to skin and ocular tissue, leading to inflammation and ulceration

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Cattle, sheep, goats: Suspected to be similarly toxic, with high risk of photosensitive dermatitis after exposure

Small companion mammals (rabbits, guinea pigs): No formal toxicity data available, exposure is not recommended as a precaution

Confusion Risk

The following plants look similar and may be confused:

Cow Parsnip Heracleum maximum

Shared Apiaceae family and clustered white flower heads lead to confusion; Cow Parsnip is larger with broader leaves and also contains furanocoumarins

Wild Carrot Daucus carota

Similar white clustered flower heads; distinguishable by its smaller size, hairy stem, edible carrot root, and general non-toxicity to most species

Use PlantFun to scan and avoid misidentificationGet App

Related Toxic Plants

Poison Hemlock

Conium maculatum

Severe toxicity, potentially fatal to all mammalian species even in small doses

Water Hemlock

Cicuta maculata

Severe toxicity, one of the most toxic native North American plants, ingestion is often fatal

Giant Hogweed

Heracleum mantegazzianum

High toxicity, causes severe blistering photodermatitis and permanent eye damage

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. ASPCA Animal Poison Control

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

View Full Plant Wiki