What does tolerability mean?
Tolerability means the quality of being tolerable: the extent to which something can be accepted, endured, or used without serious harm or inconvenience. The word is especially prominent in medicine, pharmacology, and treatment research, where a drug's tolerability describes how well patients tolerate its side effects. A medicine with good tolerability generally causes fewer or less severe adverse effects, although tolerability can also depend on dosage, duration, individual sensitivity, and the condition being treated. The term is more formal than tolerance and usually appears in technical or professional discussion. Outside medicine, tolerability can describe any experience that is merely bearable, though such usage is less common. Understanding the word is useful because it draws attention to a practical distinction between whether something works and whether patients can accept what it does to them. It also encourages assessment of acceptability and harm alongside efficacy or quality.
nounThe quality or degree of being tolerable, especially the extent to which something can be endured without serious harm, discomfort, or unacceptable effects. It is used particularly in medicine and other technical contexts.
- The quality or degree of being tolerable; acceptable endurance, especially with respect to the effects of medicine or treatment.
"The new treatment has a favourable safety and tolerability profile among most patients."
"Clinicians considered both the efficacy and the tolerability of the medication."
"Improvements in the treatment's tolerability may increase patient adherence."
Rare and normally avoided because tolerability is usually treated as an uncountable noun.
"Few studies directly compare the tolerabilities of the two regimens."
Tolerability began with endurance: something tolerable was, quite literally, something you could bear.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does tolerability come from?
Tolerability belongs to a word family derived from Latin tolerare, meaning “to bear” or “endure.” English developed related forms such as tolerate, tolerable, tolerant, and tolerance before forming tolerability with the productive suffix -ability. Over time, the meaning developed from the capacity to endure toward the broader idea of being acceptable or causing tolerable effects.
How tolerability is actually used
Most common in medical, pharmacological, and scientific contexts. In general usage it is formal and less natural than tolerance; it is normally uncountable, although the plural tolerabilities is occasionally used.
Easily confused with tolerability
Tolerance is the capacity to accept or endure something, whereas tolerability is the quality of being acceptable or endurable.
Tolerable is an adjective describing something that can be endured, while tolerability is the noun naming that quality.