1
be under a sedative
作名词时，under a sedative 表示“在镇静剂作用下”，常用于医疗语境。
The patient is under a sedative and should not be disturbed.
病人正在镇静剂作用下，不应被打扰。
镇静剂
先理解核心含义，再看它在真实句子里的用法。
镇静剂
a drug that reduces excitability and calms a person
The patient is under a sedative and should not be disturbed.
病人正在镇静剂作用下，不应被打扰。
一种镇静剂或药物,具有安抚或舒缓作用,或诱导睡眠。
An agent or drug that sedates, having a calming or soothing effect, or inducing sleep.
降低兴奋性并使人体镇静的药物
a drug that reduces excitability and calms a person
The doctor gave her a mild sedative to help her sleep before the flight.
医生给了她一种温和的镇静剂，帮助她在飞行前入睡。
After the accident, he needed a sedative to calm down.
事故发生后，他需要服用镇静剂来平静下来。
The hospital keeps strong sedatives in a locked cabinet.
医院把强效镇静剂锁在柜子里。
作名词时，under a sedative 表示“在镇静剂作用下”，常用于医疗语境。
The patient is under a sedative and should not be disturbed.
病人正在镇静剂作用下，不应被打扰。
作名词时，as a sedative 说明用途，as 后接名词。
Chamomile tea is often used as a mild sedative.
洋甘菊茶常被用作温和的镇静剂。
作形容词时，sedative 通常放在名词前修饰，如 sedative effect（镇静作用）。
This medicine has a sedative effect and may cause drowsiness.
这种药有镇静作用，可能会引起嗜睡。
Not this
The doctor gave me sedative before the surgery.
Use this
The doctor gave me a sedative before the surgery.
sedative 是可数名词，表示“一剂镇静剂”时前面要加不定冠词 a；中文“镇静剂”常不强调量词，容易漏掉冠词。
Not this
This medicine can sedative my anxiety.
Use this
This medicine can sedate my anxiety.
sedative 是名词或形容词，不能作动词；表示“使镇静”要用动词 sedate。
Not this
After taking the pill, I felt very sedative.
Use this
After taking the pill, I felt very sedated.
sedative 作形容词时意为“有镇静作用的”，通常修饰药物等事物；表示人“感到镇静的”要用过去分词形容词 sedated。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
服用镇静剂
She took a sedative to help her sleep on the long flight.
她在长途航班上服用了镇静剂来帮助入睡。
开镇静剂
The doctor prescribed a sedative for the patient's severe anxiety.
医生为这位严重焦虑的病人开了镇静剂。
温和的镇静剂
Chamomile tea is often used as a mild sedative before bedtime.
洋甘菊茶在睡前常被用作温和的镇静剂。
强效镇静剂
The hospital gave him a strong sedative before the surgery.
手术前医院给他用了强效镇静剂。
天然镇静剂
Some herbs act as natural sedatives for people who cannot tolerate prescription drugs.
一些草药对无法耐受处方药的人来说可起到天然镇静剂的作用。
镇静效果
This medication has a sedative effect and should not be taken before driving.
这种药物有镇静效果，开车前不应服用。
Use sedative naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
联想：sedative 开头像 sedate（安静的），让人安静下来的药就是镇静剂。
语域：neutral 常见场景：medical consultation、prescription drug information、discussing sleep or anxiety medication 此条目针对名词义项（镇静剂）。该词通常用于医疗、药学或谈论药物作用的场景，属于中性偏正式的说法；日常口语中也适用，但更随意的对话里也可能用 sleeping pill 等词。
没有与 /ˈsɛdətɪv/ 完全押韵的常用词。sedate 和 sedation 以 sed- 开头，但读作 /sɪˈdeɪt/、/sɪˈdeɪʃn/，与 sedative 的 /sɛd/ 开头不同；native、creative、talkative、relative 都以 -ative 结尾，但重音和元音不同，也不押韵。
Dictionary facts from ECDICT, WIKTIONARY.