副 作 用(ふくさよう)

ふくさよう

noun

side effect

medical

1. side effect, adverse effect

An undesirable secondary effect that occurs in addition to the desired therapeutic effect of a drug or medical treatment.

この薬(くすり)は副作用(ふくさよう)が少(すく)ない。

This medicine has few side effects.

副作用(ふくさよう)として眠気(ねむけ)が出(で)ることがあります。

Drowsiness may occur as a side effect.

副作用(ふくさよう)が強(つよ)いので、医師(いし)に相談(そうだん)した方(ほう)がいい。

Since the side effects are strong, you should consult a doctor.

副作用(ふくさよう) refers to side effects of medication or medical treatment. 副(ふく) means 'secondary/sub-' and 作用(さよう) means 'effect/action.'

Common expressions

副作用(ふくさよう)が出(で)る: to experience side effects
副作用(ふくさよう)が強(つよ)い: to have strong side effects
副作用(ふくさよう)が少(すく)ない: to have few side effects
副作用(ふくさよう)のリスク: risk of side effects

RELATED WORDS (common side effects):

Related words

薬(くすり): medicine
効能(こうのう): efficacy
服用(ふくよう): taking medicine

Related Words

Related: 作用(さよう) (effect, action)

Compare: 効能(こうのう) (efficacy (intended effect))

Related: 薬(くすり) (medicine)

Related: 服用(ふくよう) (taking medicine)

Compare: 薬効(やっこう) (medicinal effect)

Compare: 反作用(はんさよう) (reaction)

Related: 造影剤(ぞうえいざい) (contrast agent)

Compare: 副反応(ふくはんのう) (side effect (esp. of a vaccine))

Compare: 後遺症(こういしょう) (aftereffect)

Related: 眠気(ねむけ) (drowsiness)

Related: 吐(は)き気(け) (nausea)

Related: 頭痛(ずつう) (headache)

Related: 発疹(はっしん) (rash)

general

Added 2026.1.14 19:37 · Revised 2026.10.10 22:29

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