A wide variety of medications and substances can kill a toddler who ingests just a single dose. More than 1 million children ingest toxins in the United States every year, and more than 85% of the ingestions are unintentional. Most of the children are younger than 6 years. 
The intent of this article is not to guide treatment of poisoned children but rather to report toxic ingestions that proved fatal in small doses. The article addresses some types of toxic ingestions and those that may cause serious illness or injury, even in small quantities. 
Many of the involved toxins are common in the home or in household products. Ingestion of relatively small amounts of commonly used perfumes, cosmetics, cleaning solutions, alcoholic beverages, and other products may cause serious injury or death. Medications also are a common source of toxic ingestions in small quantities. If prior precautions are not taken, visits to the homes of friends or relatives (even grandparents) or visits from guests who bring medications into the home may result in tragedy.
Ingestion of a small number of common substances and drugs may be fatal in small doses. Most pediatric ingestions are benign. A formal risk assessment is required to allow clinical decision making on the need for resuscitation, treatment, decontamination, enhanced elimination, antidote requirement, and period of observation
The American Association of Poison Control Centers reported that in 2014, children younger than 6 years accounted for 1,029,741 of the 2,165,142 total exposures, but only 16 of the 1173 total fatalities. Thus, less than 0.002% of total exposures in that age group proved fatal. 
Pathophysiology varies according to the ingested substance. Children are particularly susceptible to injury from ingestion of small doses for the following reasons:
The low body mass of children means that a single ingested dose of a substance may easily be toxic.
While exploring their surroundings, younger children, especially toddlers, may ingest substances with objectionable tastes or odors that would be rejected by older children and adults.
The metabolic pathways of young children, particularly infants, are less developed and use sulfonation rather than glucuronidation to process some toxins.
Most ingestions by children involve nontoxic substances. More than 1 million ingestions are believed to occur annually, most involving children younger than 7 years.
Mortality and morbidity depend on the substance or drug ingested and the quantity relative to body weight (ie, mg/kg/dose).
Race- and Age-related Demographics
Race and frequency of toxic ingestions appear to have no correlation. Toxic ingestions from a single dose occur most often as unintentional ingestions by young children aged 1-6 years.