Man spraying pesticides

Important update about Paraquat (Fall 2022)

Parkinson Canada is pleased to report that paraquat is no longer registered for distribution in Canada. Paraquat was voluntarily discontinued by the only Canadian manufacturer, Syngenta. Therefore, no products containing paraquat are now registered for use in Canada.

Additionally, efforts towards class actions are ongoing. The Quebec class action, on behalf of Quebec residents, was certified: Lebeau c. Syngenta, 2022 QCCS 2831 (CanLII) (Note: document is in French). In BC, a class action representing all Canadians outside of Quebec is also working towards certification.

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

For more information, click here or contact Donna McEvoy directly at

We know pesticides have been a topic of concern for many within the Parkinson’s community and we share in celebrating this positive news. Please scroll down to read more about the relationship between pesticides and Parkinson’s.

What are pesticides

According to the Environmental Protection Agency (EPA), a pesticide is any substance or mixture of substances meant for:

  • Preventing, eliminating, repelling or lessening/reducing pests.
  • Use as a plant regulator, defoliant or desiccant to modify plant growth, cause plants to lose their leaves or cause plants to dry out.
  • Use as a nitrogen stabilizer to help prevent crop losses by manipulating plants’ access to nitrogen in the soil – an important element for plant growth.

The term “pesticide” refers to herbicides, insecticides, rodenticides, fungicides, and other chemical agents that eliminate unwanted organisms.

Pesticides of interest to the Parkinson’s community


Used for controlling different grasses and broadleaf weeds in crops (for example fruit crops, hazelnuts and vegetables) or as a pre-emergent treatment (to stop the seeds of weeds from growing and emerging from the soil). Gramoxone® is the product name in Canada for the herbicide that contains paraquat as the active ingredient. Because the use of paraquat is restricted to certified applicators by Health Canada’s Pest Management Regulatory Agency (PMRA), it is primarily used in agriculture. Gramoxone® is not available for residential use or able to be picked up at your local hardware store. Paraquat will be re-evaluated by PMRA in 2022.Currently, paraquat is banned in over 30 countries worldwide – although Canada and the U.S. are not part of this list. In 2012, the French government recognized Parkinson’s as an occupational disease among farmers who have been exposed to pesticides for more than 10 years. Recently, the province of Quebec has also recognized Parkinson’s as an occupational illness. Globally, there are numerous class-action lawsuits against the manufacturers of Gramoxone®. This includes ongoing efforts to raise lawsuits here in Canada.


While it is derived from the roots of legumes like peas and beans, Rotenone is very toxic and used to manage invasive fish species. Rotenone is sold under the product name Noxfish® and is registered for use in Canada with restrictions varying by province. Permission to use the pesticide may not be granted by certain provinces, territories and municipalities. Rotenone will be re-evaluated by PMRA in 2023.

Another pesticide often in the news due to its health implications is a product called RoundUp®. While it may have other harmful effects, presently RoundUp is not one of the pesticides of concern in Parkinson’s.

Relationship between pesticides and Parkinson’s

There is growing awareness, research and discussion regarding the relationship between pesticides and Parkinson’s. While it is extremely difficult to definitively establish a cause and effect relationship, many epidemiolocal studies and systemic reviews have found an association between exposure to certain pesticides and Parkinson’s. , , For example, in one large-scale study using data from agriculture communities in the U.S., individuals who used paraquat or rotenone in their work were roughly 2.5 times more likely to have Parkinson’s than those who did not.

Risk vs. “cause and effect”

It is challenging to identify a specific event that cause a person to develop Parkinson’s. For most cases, it is likely a combination of genetic and lifestyle factors.

As an example, we are aware that men have roughly 1.5x the risk of being diagnosed with Parkinson’s compared to women. But that does not mean all men will inevitably get Parkinson’s. Similarly, exposure to pesticides increases the risk of developing Parkinson’s, but it does not guarantee that someone will develop Parkinson’s after being exposed.

More research is required to better understand how significantly pesticide exposure increases a person’s risk of developing Parkinson’s and how risk levels change across different types of exposure (i.e., directly working with pesticides versus living in an area with pesticide use, short term exposure versus years of exposure).

What we are doing to advance the understanding of Parkinson’s and pesticides

The Parkinson Canada Research Program has funded work related to pesticides and continues to support discoveries in many areas of Parkinson’s, including research into understanding the causes of Parkinson’s.

Parkinson Canada has representation on the PD Avengers Pesticide Working Group and contributed to a World Health Organization technical brief on Parkinson’s, which includes a call to action to study and understand modifiable risk factors for Parkinson’s including pesticides.

We continue to monitor the connection between pesticide exposure and the development of Parkinson’s. More information will be provided to the community when available.

What you can do

Both paraquat and rotenone are regulated under governmental restrictions and are unlikely to be found lying around in your garage or sold in-store.

However, if you work in an industry that uses these kinds of products, there are some precautions you can take:

For more information on handling pesticides safely, visit the Canadian Government’s Use Pesticides Safely guidelines.