Meaning & use
adverse reaction
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Meanings
nouncountablemedical
An unwanted and harmful response by the body to a drug, food or treatment.
Grammar: Countable; often followed by to: an adverse reaction to penicillin.
Patterns
- an adverse reaction to something
- have an adverse reaction
She had an adverse reaction to the antibiotic and developed a rash.
Doctors asked patients to report any adverse reaction after the injection.
An adverse reaction to peanuts can be dangerous.
nouncountableformal
A strongly negative response from people to an action, decision or announcement.
Grammar: Often followed by to: an adverse reaction to the news.
Patterns
- an adverse reaction to something
The announcement caused an adverse reaction among investors.
The plan met an adverse reaction from local residents.
The film received an adverse reaction from critics.
Word forms
| plural | adverse reactions |
|---|
Common combinations
- have an adverse reaction
- He had an adverse reaction to the new medicine.
- cause an adverse reaction
- Some foods can cause an adverse reaction in children.
- report an adverse reaction
- Patients should report any adverse reaction to their doctor.
- serious adverse reaction
- A serious adverse reaction needs urgent care.
- adverse reaction to a drug
- An adverse reaction to a drug may involve vomiting.
Synonyms and how they differ
- side effect
- A side effect may be mild and expected, whereas an adverse reaction is clearly harmful and unwanted.
- allergic reaction
- An allergic reaction involves the immune system specifically, while adverse reaction covers any harmful response.
- backlash
- Backlash only applies to public or social response, not to the body.
Opposites
Word family
Commonly confused: adverse reaction or averse?
adverse reaction vs averse
Averse means strongly unwilling, as in not averse to hard work. Adverse means harmful or unfavorable, as in adverse weather.
Practice
Her body had an adverse reaction ___ the new medication.
Choose one answer.
Reaction to something is the standard pattern. At, for and from sound plausible but are not used with this phrase.
Make it your own
Write a sentence using “adverse reaction”, then check it and compare it with the examples above.