Pesticides are poisons designed to impair or destroy biological organisms. Because all life on Earth shares a similar biology (a neuron is a neuron whether it’s in a human or a flea) there isn’t a pesticide on the planet that is going to be completely benign once it gets inside your body. Some are better than others, but pesticides as a whole are some of the most toxic chemicals we have, and all come with a long list of related health problems.

Pesticides are known to cause cancer, disrupt hormones and cause brain damage in children. They are highly toxic to the nervous system. They impair immune system functioning, harm your heart, and contribute to obesity. They are responsible for miscarriages and birth defects. They destroy cells and cause genetic damage that can be passed down through generations. Though each pesticide creates its own unique health problems (each of which are covered in our e-book Toxic Childhood), there are many familiar themes that cut through almost all of them.

How pesticides harm human health

A 2006 study was able to count some 63 different hormone disrupting pesticides, and 60% of all herbicides that are widely used are capable of disrupting hormones. (Colburn, 2006) Since hormones play a role in virtually every function in the body, the list of possible health consequences is almost endless. (See the section on Endocrine Disrupting Chemicals in our e-book Toxic Childhood)

A number of pesticides have a pronounced effect on the reproductive system, causing sexual abnormalities in babies and contributing to de-masculization of men. As Philip and Alice Shabecoff remark, “Pesticides could become the ultimate male contraceptive.” (2010, p. 100)

The link between pesticides & cancer

Pesticides can trigger cancer by damaging the genetic material inside cells which then leads to abnormal cell mutations. They can also indirectly contribute to cancer by impeding the immune system in a way that lowers your body’s ability to fight off cancerous growths. “Plotted geographically on a map of the United States,” write Shabecoff and Shabecoff, “cases of non-Hodgkin’s lymphoma are clearly clustered in agricultural areas likely subjected to pesticides; plotted temporally, the cases creep upward in frequency over the years as the use of pesticides increases.” (ibid, p. 56; Sanborn et al., 2004)

A CDC fact sheet on cancer clusters (accessed 1-12-2017) states that “Home pesticide use overall has been linked to childhood cancers such as soft tissue sarcomas, leukemia, and cancer of the brain.” They note that high levels of two organophosphate metabolites were found in a CDC study on childhood leukemia:

  • 3, 5, 6-Trichloro-2-pyridinol, which is a metabolite of chlorpyrifos
  • Diethylthiophosphate, a metabolite of numerous organophosphates.


Genetic damage & long-term effects

Like many chemicals, pesticides can alter the DNA and RNA inside cells by damaging portions of a gene sequence while binding to receptors like epigenetic methyl tags, thus altering the expression of others. Wesley Marx notes that the genetic damage done from pesticide exposure can even be passed down from parent to child, an effect that ripples through the generations. “This pesticide heritage,” one scientist told me, “may be the twentieth century’s version of original sin.” (Marx, 1967, p. 64)

Pesticides & mental illness

There’s also evidence that pesticides can lead to mental health problems. As Natalie Gingerich Mackenzie (2012) writes, “Numerous studies have found that farmers who work with pesticides have as much as six times the risk of depression; even farmers’ wives who use sprays in their homes and backyard gardens have nearly double the risk.”

Additional health effects from pesticides

  • Research suggests many pesticides adversely affect heart health, leading to heart arrhythmias, a slowing heart rate or other nerve-related abnormalities in the heart.


  • Pesticide exposure is linked to Parkinson’s disease. (Shabecoff & Shabecoff, 2010, p. 100)


The consequences of pesticide use

As Dr. Andrew Weil states, “I cannot emphasize too strongly that residues of toxic chemicals in foods we eat are major health hazards, affecting us in ways that current medical science and governmental policy often fail to recognize.” (Weil, 1995, p. 164) He notes that the “acceptable” levels of pesticide residue on produce (much of which can’t be washed off or has been absorbed into the produce itself) is based on guidelines set around often arbitrary numbers recommended by the agriculture industry which don’t necessarily reflect actual safety.

Alex Lu, professor of environmental exposure biology at the Harvard School of Public Health, states that “Federal guidelines don’t take into account what effect repeated exposure to low levels of chemicals might have on humans over time. And many pesticides were eventually banned or restricted by the federal government after years of use when they were discovered to be harmful to the environment or human health.” (Lu, 6-17-2013)

Moreover, just because a pesticide is banned in the U.S. does not mean your family is entirely protected from it. U.S. companies manufacture tons of banned pesticides to be shipped overseas, which are then applied to crops in other countries and sent right back to the U.S. on the produce we import. This means that although certain toxic pesticides aren’t allowed to be sprayed on U.S. soil, your family can still ingest traces of them in the food you eat.