MSF is assisting around 20,000 civilians from Fallujah who have fled to three main sites. The Islamic State group seized the city more than two years ago.
The head of MSF’s mission in Iraq, Fabio Forgione, said families who have fled to camps are facing a lack of shelter and clean drinking water. A cholera outbreak last year infected some 2,800 people in Iraq.
He said doctors are also treating people with conditions such as high blood pressure and diabetes who haven’t had access to medications.
Food shortages have also been reported in the city.
MSF has deployed mobile health clinics near the front-lines to provide basic services to families who have escaped. Fallujah is located 65km west of Baghdad.
The UN estimates that 50,000 civilians are trapped inside the city and 42,000 people have fled Fallujah since a military operation to retake the city began in late May.
Organisations such as MSF and the Norwegian Refugee Council say the number of those who have fled is closer to 30,000.