When someone is told by a doctor to stay in bed, the phrase we use is "on bed rest." You can use it like this:
- His grandfather was admitted to the hospital and put on bed rest.
- Even though he was released from the hospital, he was put on bed rest at home for the next six weeks.
You can also use "bedridden."
- Jane caught the flu and was bedridden for the whole week.
There is also "confined to bed."
- His grandfather was hospitalized last week and confined to bed.
医者からベッドで安静にしているように言われたときは、"on bed rest" というフレーズが使われます。
例えば：
- His grandfather was admitted to the hospital and put on bed rest.
（彼の祖父は入院して、安静を命じられました）
- Even though he was released from the hospital, he was put on bed rest at home for the next six weeks.
（彼は退院したものの、自宅で6週間の安静を命じられました）
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"bedridden" も使えます。
- Jane caught the flu and was bedridden for the whole week.
（ジェーンはインフルエンザにかかって、まる一週間寝たきりでした）
"confined to bed" もあります。
- His grandfather was hospitalized last week and confined to bed.
（彼の祖父は先週入院して安静を命じられました）
日本 
アメリカ合衆国 
