The likelihood of producing a significantly larger-than-average response to a
specified exposure to a substance.
Susceptibility can be subdivided into innate and acquired susceptibility.
Innate susceptibility may be due to genetic predisposition or
to incomplete development of normal (adult) physiological functions. A young
child may be susceptible to a given substance because detoxification processes
are not yet fully developed. Such susceptibility is transient and disappears
with age and growth.
Acquired susceptibility may be due to disease, socioeconomic
status or age.