Last edited 11 Jan 2021

Poisonous plants and construction

Outdoor work can be hazardous - even with appropriate health and safety policies and risk assessments - if employees do not understand the risks and receive appropriate training to manage their own PPE responsibilities, then they may be putting themselves at increased risk.

The UK has its share of poisonous plants that may cause rashes, illness, and - in rare cases - death. When working in remote locations, or on building sites, make sure to assess the dangers on site, and remove (if possible) any plants that may cause harm to workers. The following plants are poisonous when ingested, but mostly skin irritants.

Plants that are skin irritants:

  • Wolf’s Bane: Cases of accidental poisoning are rare, but the plant’s toxins can slow the heart rate, cause upset stomach, and can be fatal. Only handle with gloves.
  • Stinging Nettles: A common sight in the UK, nettles have needle-like hairs which penetrate the skin and sting you. It’s accompanied by burning, itching, and rash. Use dock leaves to neutralise and cool the skin.
  • Giant Hogweed: This plant grows up to five metres tall (16 feet) along footpaths and riverbanks, and the plant’s sap can cause severe painful burns if it comes into contact with the skin. It will make the skin sensitive to strong sunlight. Wash affected areas with soap and water. The blisters heal slowly and can cause phytophotodermatitis, which flares in sunlight. If you feel unwell after exposure, go to your doctor.
  • Thorny Plants: Needles and spines from roses, holly, blackberry bushes, and brambles can cause infections on the skin. If you are stuck by a thorn, remove the thorns and soak the area in warm water. Wear protective gloves around these plants.
Wolf’s Bane: Photo credit: Wolf.jpg Stinging Nettles: Photo credit: Nettle.jpg
Giant Hogweed: Photo credit: Hogweed.jpg Thorny Plants:Photo credit: Thorny.jpg

Plants that are poisonous when ingested:

These plants have leaves, berries, fruit, flowers, sap, or bulbs that can poison you if you eat them or give you a rash if you touch them.

  • Poison hemlock

Photo credit: Dendroica cerulea via Visual Hunt / CC BY-NC-SA


  • Foxgloves

Photo credit: dierken via VisualHunt / CC BY


  • Lords and ladies

Photo credit: Johnson Cameraface via VisualHunt / CC BY-NC-SA


  • Deadly nightshade

Photo credit: Plbmak via / CC BY-NC-ND


  • Yew

Photo via


  • Daffodil Bulbs

Photo credit: delayedneutron via / CC BY-NC-SA


  • Chrysanthemums

Photo via


  • Snowdrops

Photo credit: matthewvenn via Visual Hunt / CC BY-SA


  • Mistletoe

Photo credit: bluefuton via Visualhunt / CC BY-NC-ND


Avoid touching these plants where possible, and do not eat them.

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[edit] Related articles on Designing Buildings Wiki


With reference to nettles and using dock leaves to alleviate the rash... try plantain leaves, they are way better!

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