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Gramoxone® is a non-selective herbicide used to control broadleaf weeds and grasses with an active ingredient called paraquat.  It is alleged that paraquat exposure is linked to Parkinson’s disease.

Siskinds Desmeules, Siskinds LLP’s Quebec-based affiliate, has filed a class action lawsuit on behalf of all Canadians who have been diagnosed with Parkinson’s disease after using and/or being exposed to Gramoxone®, since July 1, 1963.


Paraquat, also known as paraquat dichloride or N,N′-dimethyl-4,4′-bipyridinium dichloride, is a toxic chemical used as a herbicide marketed under the name Gramoxone® and manufactured by the Syngenta entities since 1963.  It is often sold as a liquid concentrate with a dark blue-green color and a strong, sour or putrid, odor.

According to several studies, exposure to paraquat, the main active ingredient in Gramoxone®, increases the risk of developing Parkinson’s disease.

For example, a 2013 study found that exposure to this herbicide doubled the risk of developing Parkinson’s disease and a 2015 study established a link between paraquat and Parkinson’s disease for non-users of protective gloves during exposure to the active ingredient. The results of several other studies have also identified an increased risk ratio for developing Parkinson’s disease following exposure to paraquat.

Parkinson’s disease

Parkinson’s disease is a neurodegenerative disease of the brain that primarily affects the motor system, the part of the central nervous system that controls movement.

The characteristic symptoms of Parkinson’s disease consist of primary and secondary motor symptoms and non-motor symptoms.

  • Primary motor symptoms: tremor at rest, bradykinesia (slowness of voluntary movements), rigidity and postural instability.
  • Secondary motor symptoms: freezing of the gait, narrowing of the handwriting, slurred speech, muscle spasms, coordination problems, difficulty swallowing and excess saliva caused by reduced swallowing movements.
  • Non-motor symptoms: loss or altered sense of smell, constipation, hypotension on getting up, sleep disturbances and depression.

Legal proceedings

Siskinds Desmeules is seeking financial compensation on behalf of all Canadians who have been diagnosed with Parkinson’s disease after using and/or being exposed to Gramoxone® and its active ingredient, paraquat, since its entry into the Canadian market (on or about July 1, 1963).

Siskinds Desmeules filed an application for authorization to bring a class action before the Quebec Superior Court alleging that the manufacturers failed in their obligations by making false representations regarding to the safety of Gramoxone® and paraquat, and that they failed in their obligations by not providing adequate, sufficient and timely warning to the proposed class members of the risks associated with the use and/or exposure to Gramoxone® and paraquat, as well as the extent of those risks, in particular that of developing Parkinson’s disease.

If you have used and/or been exposed to Gramoxone® (and its active ingredient, paraquat) and have Parkinson’s disease or if you know someone who has, Siskinds Desmeules may be able to help.

For more information, visit siskinds.com/class-action/gramoxone-paraquat or contact our team.

If you are a member of Quebec, you can reach Siskinds Desmeules at:

Phone: 418-694-2009 (or toll free at 1-877-735-3842)
Email: [email protected]
Postal address: 43, rue de Buade, bur. 320, Quebec (Quebec) G1R 4A2

If you are a member of other Canadian provinces, you can reach Siskinds LLP at:

Phone: (416) 594-4793
Email: [email protected]
Mailing Address: 680 Waterloo Street, London, Ontario N6A 3V8

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