Nasri received 500 millilitres of hydration in the form of sterile water containing micronutrient components on December 26, 2016, while on holiday.
It is understood that the 30-year-old French player took the treatment while on holiday, but it contravened World Anti-Doping Agency (Wada) rules leading to a Spanish Anti-Doping investigation.
Samir Nasri has been banned from football for six months because of a drip treatment he took in 2016.Download Our ANDROID APPLICATION now! DOWNLOAD NOW
— BBC Sport (@BBCSport) February 27, 2018
UEFA imposed the suspension, which it says is open to appeal.
The Frenchman received treatment from a private medical company, Drip Doctors, in his hotel room.
At the time he was on loan from Manchester City to Sevilla and posed for a photograph with the organisation’s co-founder Jamila Sozahdah that drew publicity.
Wada rules state there is a 50 millilitre infusion limit per six-hour period for active athletes but it was alleged he received 500 millilitres of hydration in the form of sterile water containing micronutrient components.
In February 2017, a request by Sevilla for a retroactive therapeutic use exemption (TUE) for Nasri was refused by Uefa, whose decision was later upheld by the Court of Arbitration for Sport.
Nasri is currently without a club, having left Antalyaspor in January after just six months with the Turkish team.
The 30-year-old former France international played for Arsenal from 2008 to 2011 before moving to City for £25million, going on to win two Premier League titles during his time at the Etihad Stadium.
During his loan spell at Sevilla last season he made 30 appearances and scored three goals.