Toxic plants

Heracleum sosnowskyi - Sosnowsky's hogweed

Sosnowsky's hogweed


Heracleum sosnowskyi, the Sosnowsky's hogweed, is a flowering plant in the family Apiaceae, originally native to Caucasus. Now it is a common weed in the Baltic States, Belarus, Russia, Ukraine, and Poland.

All parts of H. sosnowskyi contain the intense toxic allergen furanocoumarin. It is dangerous for humans because even small drops of plant's juice cause photosensitivity and burns.

Sosnowsky's hogweed is a highly invasive plant in the Baltic States, Poland, and Belarus. Many river valleys and roadsides are occupied by large stands of this weed. It is difficult to eradicate because the seeds remain viable for many years and the roots are difficult to remove. Herbicides are widely used in a fight against it, but the plant can later resprout from the roots.

Description based on the Wikipedia article: [1]


Toxicity. Furanocoumarin contained in the plant secretions is a threat to human health. These allergens with contact with the human skin in the presence of sunlight cause second and third-degree burns. The first symptoms may appear after few minutes of exposure to ultraviolet radiation. The most intensive symptoms appear after 30 minutes to 2 hours from the contact with the plant. This long time from the exposure to the first symptoms is especially dangerous because people may ignore presence of Hogweed. Kids, gardeners or farmers may spend more time near the Hogweed and be exposed to more burns.

The strength of the reaction is related to the personal resistance of the individual. The plants are more dangerous in high temperatures and high humidity. Stronger reaction is also linked to the amount of sweat of the individual.

Within 24 hours worsen symptoms occur. There are i.e. redness of the skin (erythema) and blistering of serous fluid (edema). Inflammation persists for about three days. After a week in the exposed area the skin is getting darker (hyperpigmentation occurs). This condition may persist by several months. Burned skin areas are sensitive to the ultraviolet radiation by several years. Some of the furanocoumarins produced by this species are carcinogenic and teratogenic.

Description based on the Wikipedia article: [2]


Prevention. Ways of prevention:

  • Direct contact avoidance
  • Protection of skin by wearing the synthetic and waterproof clothes
  • Protection of eyes by wearing goggles

After direct contact with the Hogweed:

  • Immediately wash skin with soap and water
  • Avoid sunlight for 48 hours

Description based on the Wikipedia article: [3]


Data. Data comes from the official public administration sites annoucements (Polish titles).

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