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Why the Adage 'the Dose Makes the Poison' Can Be Toxic to Corporate Chemicals Policy

There probably are lots of senior execs who've been comforted when their chief scientist has told them that since "the dose makes the poison," they shouldn't sweat some new study about a chemical found in small amounts in their products. This maxim is somewhat misleading; taking it at face value may be toxic to your company's reputation.

There probably are lots of senior execs who've been comforted when their chief scientist or toxicologist has told them that since "the dose makes the poison," they shouldn't sweat some new study about a chemical found in small amounts in their products. Unfortunately, this maxim, which has been around for about 500 years, is somewhat misleading; taking it at face value may be toxic to your company's reputation.

You're better off heeding an updated version: "The dose and the timing make the poison." This can steer you toward seeking safer alternatives for your products that will help build trust with your customers, particularly the demographic that cares about the health and development of the youngest, oldest and most vulnerable among us.

We know lots more now about human development than was known in the 1500s when Paracelsus coined the phrase that has been handed down as "the dose makes the poison." The roughly 40-week process of human development in the womb is truly remarkable. The brain and the rest of the nervous system develop. So too do the immune, endocrine, reproductive and other systems. Add in arms, legs, internal organs and a host of other systems and structures.

The whole process is driven by carefully balanced and infinitesimally small amounts of naturally produced biochemicals. Assuming a healthy genetic inheritance, the odds of the process yielding sound development are pretty good if the right chemicals are produced in the fetus as they should be, and are delivered in the correct amounts in the appropriate places at the required times. Regrettably, it doesn't take much of the wrong outside chemical to foul up this exquisitely orchestrated progression. The results of such interference might show up immediately at birth in the form of some gross birth defect; or, more insidiously, may be delayed a little later in childhood as learning or behavioral problems; or delayed later still in the form of an enhanced risk of testicular cancer in young men, breast cancer in women, or other health disorders. Many of these effects can be irreversible and permanent.

Concern about chemicals in the womb will only multiply as research on humans' acquired chemical load, or body burden, increases. The U.S. Centers for Disease Control has released a series of three reports delineating Americans' body burdens, and a fourth is scheduled for later this year. The list of chemicals found in Americans reads like a who's who of substances commonly found in every day products. In 2005, two environmental health nonprofit organizations, looking earlier in the development process than the CDC routinely does, published a study of umbilical cord blood that revealed the presence of scores of common chemicals including pesticides, brominated flame retardants, and chemicals used as stain and oil repellants in packaging and on textiles.

Scientists are careful to caution that the presence of an alien chemical doesn't necessarily mean some health problem is preordained and that is sometimes the case. But by the same token, there's no doubt we know astonishingly, depressingly little about the effects of small amounts of most chemicals. Even worse, the science emerging in recent years signals that the more we learn, the more we ought to be concerned. Most chemicals are severely under-researched and most of the health effects research conducted has been done by testing high doses of chemicals on healthy adult laboratory animals. The assumption underlying much of this high dose testing is that as doses go up, effects do, and vice-versa. But this is not necessarily so; effects can show up at low doses that are absent at high ones; consequently, high dose testing, by missing effects that can show up at low doses, provides misleading assurances about chemical safety.

Even worse, the mixtures to which we're commonly exposed have rarely been tested for their additive or synergistic effects. Some of the modest amount of mixtures research even suggests that when chemicals are mixed at levels believed to be individually safe, the cumulative effect can be toxic.

Because relatively little research has been done on exposures to chemicals in the womb and early in childhood, public assurances of chemicals' safety rest on a base of "lamppost science." The expression stems from the apocryphal tale of the policeman encountering a drunk on his hands and knees under a light post. When queried about his behavior, the drunk tells the officer he's lost his keys and is looking for them. The officer asks, "You lost them here?" The drunk responds, "No, I lost them over there, but the light's better over here."

Newer science showing undesirable chemical effects on development in the womb -- shedding light into areas that hitherto have been scientifically dark -- may uncover the keys to disturbing increases in various human health problems. Ongoing research is leading some science and medical experts to conclude that increases in autism, childhood asthma and learning disorders may be linked to chemical exposures at levels well below what is considered safe by traditional "dose makes the poison" thinking.

In early June, The Endocrine Society, a professional society of 14,000 members devoted to research on hormones and endocrinology, issued a landmark statement (PDF) capturing this scientific paradigm shift. The lead sentence from the USA Today story about the study reads: "Hormone-like chemicals in plastics, pesticides and other products pose 'significant concern for public health,' possibly causing infertility, cancer and malformations, a medical society announced Wednesday." The story goes on to cite one of the statement's authors, Andrea Gore from the University of Texas-Austin, as commenting that even small doses can cause serious problems, especially if babies are exposed during critical development windows (such as before birth) and, for hormones, the timing of exposure is often far more critical than the amount.

USA Today cited the American Chemistry Council as responding "that a group called the International Union of Pure and Applied Chemistry found there have been no 'conclusive' studies proving that the chemicals cause disease." That's eerily reminiscent of the American tobacco industry blowing off the U.S. Surgeon-General's early warnings about smoking.

So if you're a senior corporate strategist and a controversy erupts over some chemical found in small amounts in your product, if your science advisor or trade association says "the dose makes the poison," get a second opinion. To avoid toxic lockout (PDF) from markets and to lower your company's toxic footprint, look to where science is headed rather than relying on the lamppost science of the past.

(Editorial Note: This essay benefited from review comments provided on an initial draft by a half dozen professional acquaintances with backgrounds in pediatric medicine, public health, biology, chemistry, civil engineering and toxicology. I'm solely responsible for this final version.)

Richard A. Liroff, Ph.D, is founder and director of the Investor Environmental Health Network (IEHN). IEHN is a collaboration of investment managers that advocates for safer corporate chemicals policies to grow long-term shareholder value and reduce financial and reputational risks to companies. The business case for corporate safer chemicals policies, a list of shareholder resolutions on safer chemicals policies, and a roster of participants can be found on the IEHN Web site,

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