Given a large enough exposure, all substances have the potential to be poisons. Inadvertent exposures to substances that meet specific criteria are considered “nontoxic” and require only that the exposed patient undergo a brief observation period prior to discharge (Table 170-1).

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Table 170-1 Criteria for Nontoxic Ingestions 

Poisoning occurs when exposure to a substance adversely affects the function of any system within an organism. The setting of the poison exposure may be occupational, environmental, recreational, or medicinal. Poisoning may result from varied portals of entry, including inhalation, insufflation, ingestion, cutaneous and mucous membrane exposure, and injection. Historically most poisonings have occurred when substances are tasted or swallowed. Toxins may be airborne in the form of gas or vapors or in a suspension such as dust. Caustics, vesicants, or irritants may directly affect the skin, or a toxin may pass transdermally and affect internal structures (e.g., methylene chloride, aniline dye). Parenteral exposure results from IV or SC injection of medications or drugs of abuse, or after high-pressure injection (e.g., hydraulic fluid).


A poison may affect the normal activity of an organism in a variety of ways. It may inhibit or alter cellular function, change organ function, or change uptake or transport of substances into, out of, or within the organism. The toxin may prevent the organism from obtaining or utilizing essential substrates from the environment.


In 2008, almost 2.5 million toxic exposures were reported to poison control centers in the U.S., with 1315 deaths related to the toxin or drug, with 58% involving children <12 years of age.1 Although frequently referred to as “accidents,” most such incidents are preventable. The primary principle of poison prevention is education: school counselors, primary care physicians, and emergency physicians can inform families about poisonings, potentially poisonous substances, and techniques for protecting children from their environment. Nonfood (potentially harmful) items should never be stored in food areas, and toxins should never be stored in empty food containers. Physicians, hospitals, and pharmacies can work ...

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