side effect
Meaning of side effect: A side effect is any effect of a medication, procedure, or other treatment beyond the one it was specifically intended to produce.
Definition of side effect
A side effect is an effect of a medication, procedure, or other treatment that occurs in addition to its intended, primary effect. Side effects can arise from medications of any kind, from surgery, from radiation treatment, and from many other medical interventions, not only from cancer treatment.
Some side effects are mild and temporary, resolving once the treatment ends or the body adjusts, while others are more persistent or serious and may influence how a treatment is used or whether it is continued. A given side effect may also be more or less likely depending on the dose, duration, or combination of treatments involved.
Side effect is sometimes used interchangeably with adverse effect in everyday conversation, though the two are technically distinct, since adverse effect specifically implies a harmful or unwanted result, whereas side effect can, in principle, describe any secondary effect, whether harmful, harmless, or occasionally beneficial.
Used in a sentence
The patient was monitored for side effects after starting the new medication.
Good to know
Side effect and adverse effect are often used as if interchangeable, but adverse effect specifically implies harm, while side effect technically includes any secondary effect regardless of whether it turns out to be harmful.