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Chlormequat was found in oat products. Can you still eat your Cheerios?

Qianzhi Jiang, PhD, RDN, LDN


baby eating cheerios
My 2 year old daughter eating Cheerios

Take Away Messages 

  • Chlormequat is a pesticide or plant growth regulator used in grain and produce production.

  • Animal studies have shown adverse effects on fertility and metabolic indicators. Human studies are lacking. 

  • Organic oats and a diverse diet can minimize the exposure to chlormequat. 

Oats have long been considered as a healthy whole grain and promoted by many health professionals for various clinical benefits. Recent research done by the Environmental Working Group (EWG) may say otherwise. 

Researchers have detected chlormequat (a pesticide used to regulate plant growth) in most oat products including Cheerios and Quaker Oats. They have also found significantly higher concentrations of chlormequat in urine samples collected in 2023 compared to samples collected prior to 2023. 

This leads to a number of questions in the general public. What is chlormequat? What will happen if it is eaten? Can we still enjoy our Cheerios or Quaker Oats?

What is chlormequat?

Chlormequat (found in the format of chlormequat chloride) is a pesticide used to promote sturdier, thicker stalks in plants with increased grain yield. It can also help produce larger, better fruits. 

It was first discovered in the late 1950s and successfully used on wheat. It creates more flexibility and ease of use for farmers who grow small grains like wheat, barley, oats, and triticale (a hybrid of wheat and rye). It is also commonly used in floriculture to promote flowering. 

Nowadays, chlormequat is approved for use in the UK, EU and Canada primarily on food crops as well as beans, peas and ornamental plants. In the US, it is currently only allowed on ornamental plants but not edible plants such as grains and vegetables. 

Chlormequat has been found in some fruits and vegetables such as pears and peppers in Europe possibly due to contamination. 

The U.S. Environmental Protection Agency (EAP) started to allow imported wheat, oats, and barley treated with chlormequat from Europe and Canada in 2018 and increased how much chlormequat was allowed in oats in 2020.

Under high temperatures during food processing, chlormequat may be naturally formed in wheat products and egg powder at a low concentration.

What does the research say?

Animal studies have shown impaired fertility in pigs with 70% of their diet from wheat treated with chlormequat, and compromised fertilizing ability in test tubes of sperms isolated from male mice when exposed to chlormequat, but not in female mice. 

A recent rat study published in 2020 found disrupted growth of the embryos characterized by a longer head and a heavier brain. The offspring after birth also showed increased blood lipid levels and reduced blood glucose levels. 

The rats in this study were exposed to chlormequat at 5 mg/kg body weight during pregnancy. This is 100 times the reference dose (RfD) (0.05 mg/kg body weight) set by the U.S. EPA and the acceptable daily intake (ADI) (0.04 mg/kg body weight) published by the European Food Safety Authority, which is the default factor used in most chemical risk assessments. This means, if an animal study discovers adverse health effects when exposed to a chemical, the safety intake value in humans should be set at a level that is 100 times lower than the level used in the animal study.

Therefore, the rat study provides a reason for the EPA to reevaluate the current RfD for chlormequat. More studies done in humans are needed to provide better guidance. 

According to the EPA, there are no dietary risks of concern when they combine dietary and residential exposures. The EPA has also concluded that there are no identified risks to animals and plants living in the water and on the land that are exposed to chlormequat. 

In fact, the EPA proposed in 2023 to allow the use of chlormequat as a pesticide in the US with mitigation measures to minimize occupational exposure in personnel involved in agricultural production. 

Can you still eat your Cheerios?

The short answer is yes. The long answer is you may want to adopt strategies to minimize your exposure to chemicals like chlormequat while still enjoying a cold bowl of Cheerios with milk or some warm oatmeal with cinnamon and sliced bananas. 

For consumers who want to minimize their exposure to chlormequat and who can afford the food cost, organic oats are an option as they are free of most synthetic pesticides including chlormequat. 

Another strategy that can help reduce the risk of toxicity from any chemical is to include a variety of cereals and grains. Agricultural and dietary diversity not only can provide essential nutrients, but can also decrease the exposure to foodborne toxins. 

Here are some tips that can help you increase the diversity of your diet:

  • Plan your weekly menu in advance so you do not always go for the easiest, quickest option

  • Include as many whole grain options as possible (whole wheat bread and pasta, brown rice, barley, quinoa, millet, farro, popcorn, yes, you read it right, popcorn)

  • Make your own meals when possible so you know what ingredients go into the dishes

  • Explore different cuisines to expand the selection of food in your diet

  • Be aware of the portion sizes to avoid over-eating anything



Overall, there has not been enough evidence to understand how chlormequat may affect human health. The detected concentrations of chlormequat in the oat products and the small urine samples of humans are well below the current RfD set by the EPA. Choosing organic oats and incorporating a variety of whole grains into the diet can minimize dietary exposure to chlormequat and many other chemicals.

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