How can you tell if wild blackberries are poisonous?

Blackberries grow wild across much of North America and parts of Europe. While most wild blackberries are perfectly safe to eat, some can make you sick. So how do you know if the blackberries you find in the wild are safe to eat or potentially poisonous?

What are some signs that wild blackberries may be poisonous?

Here are some things to look out for when identifying wild blackberries:

  • Strange or unpleasant odor – Safe wild blackberries should have a pleasant, sweet smell. If the berries smell bad or unusual, they may be poisonous.
  • Bitter taste – Take a small bite of a berry first. If it tastes very bitter or unpleasant, spit it out immediately.
  • Thornless stems – Most non-cultivated blackberry bushes have thorns on their stems. Thorns help protect the fruit. If a wild blackberry lacks thorns, it may be poison false blackberry.
  • White or green berries – Ripening blackberries tend to progress from red to black. Green or white berries are a warning sign.
  • Abnormal appearance – Shriveled, malformed, or discolored berries can indicate toxicity.
  • Upset stomach or other ill effects after eating – If you experience nausea, cramps, or diarrhea soon after eating wild blackberries, they were likely poisonous.

What are some types of poisonous wild blackberries?

There are a few species and varieties of toxic wild blackberries to watch out for:

  • Poison False Blackberry – Also called poison oak blackberry. Resembles a blackberry bush but lacks thorns. Berries are usually white/greenish.
  • Himalayan Blackberry – Invasive species with very prickly stems. Young green berries are toxic when unripe.
  • Nightshade Blackberry – Closely related to deadly nightshade. Red berries lack the typical blackberry flavor.
  • Trailing Blackberry – Native to western North America. Unripe green berries can cause stomach issues.

Where do poisonous wild blackberries grow?

Poisonous blackberry species can be found growing in the following regions:

  • Poison False Blackberry – Eastern and southeastern United States
  • Himalayan Blackberry – Pacific Northwest region from California to Canada
  • Nightshade Blackberry – Parts of southern and eastern United States
  • Trailing Blackberry – Western North America from California to British Columbia

Always be very cautious when foraging for wild berries, especially if venturing off trail. Having an experienced forager help identify your location can ensure you avoid patches of poisonous berries.

What do poisonous wild blackberries look like?

Here are some identification features of toxic wild blackberry species:

Poison False Blackberry:

  • Shrub lacking thorns on stems
  • Leaves are saw-toothed in groups of three
  • Flowers are small and white with five petals
  • Berries are oval-shaped, greenish-white or cream colored

Himalayan Blackberry:

  • Very thorny shrub growing in dense thickets
  • Leaves are groups of three or five leaflets with toothed edges
  • Flowers are white to pink with five petals
  • Immature berries are hard, green and toxic

Nightshade Blackberry:

  • Upright shrub with reddish stems lacking thorns
  • Leaves grow in groups of three leaflets
  • Small bell-shaped purple or brown flowers
  • Berries are round, red and resemble tomatoes

Trailing Blackberry:

  • Long, trailing vines with thorns
  • Leaves have three leaflets with toothed edges
  • Flowers are white with five petals
  • Unripe berries are hard and green

What makes wild blackberries poisonous?

Wild blackberries contain toxic substances that can cause harm if ingested:

  • Cyanide – Present in vegetative parts like leaves, stems and unripe berries. Interferes with oxygen utilization.
  • Lectins – Proteins found in many blackberry species. Can damage gut lining.
  • Tannins – Polyphenols that deter herbivores. High concentrations cause stomach upset.
  • Paraquetiapine and atropine – Poisonous alkaloids in nightshade blackberries.

Levels of toxicity depend on the berry species, stage of ripeness, and quantity consumed. Children are especially sensitive.

What are symptoms of blackberry poisoning?

Eating toxic wild blackberries can cause the following symptoms:

  • Nausea, vomiting, diarrhea
  • Stomach cramps, intestinal pain
  • Dizziness, headache
  • Altered mental state, confusion
  • Rapid heart rate, irregular heartbeat
  • Difficulty breathing
  • Collapse, unconsciousness

Onset of symptoms usually occurs within 1-6 hours of ingestion. Seek immediate medical care if poisoning is suspected.

How can you avoid poisonous wild blackberries?

Use these foraging tips to stay safe when gathering wild blackberries:

  • Learn how to positively identify edible blackberry species in your area.
  • Pick berries only from healthy looking bushes. Avoid sickly plants.
  • Inspect berries closely before eating. Watch for discoloration, holes, or mold.
  • Only pick ripe, dark purple-black berries. Unripe green berries can be toxic.
  • Eat a small amount at first and wait to check for ill effects.
  • Teach children not to eat wild berries without supervision.

When in doubt, remember that domesticated blackberry cultivars available in grocery stores are guaranteed edible and safe.

Can you eat poisonous wild blackberries when cooked?

Cooking toxic wild blackberries will not necessarily make them safe to eat. Here are some cooking safety tips:

  • Only collect berries you have positively identified as edible.
  • Heating can break down some toxins like cyanide, but not others like paraquetiapine.
  • Boiling may leach out harmful tannins, but some alkaloids persist.
  • Berries still may cause an allergic reaction or other sensitivity when cooked.
  • If you experience any symptoms after eating cooked berries, discard the rest immediately.

Overall, it is not worth the risk to intentionally eat any wild berries you cannot confidently identify as safe. Foraging for blackberries should be done with great care and caution at all times.


Wild blackberries can look enticingly similar to edible varieties, but some contain compounds toxic to humans. To avoid poisoning, learn how to positively identify each species in your area, look for warning signs like white berries or lack of thorns, and only pick ripe, black berries from healthy plants. When in any doubt, do not eat wild berries raw or cooked. Foraging for blackberries should only be done with great caution and care taken to avoid accidental poisoning. Stick to trusted cultivated varieties from the store when possible.

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