The court which will try the medics was set up under an emergency law declared by King Hamad ahead of a crackdown on protests mainly involving the Shia-Muslim majority of the country in March.
Some of the released doctors had been on hunger strike for more than a week.
An independent group of foreign experts set up by King Hamad al-Khalifa to investigate the crackdown said more than 100 detainees had gone on hunger strike.
Seventeen of them were hospitalised after their health deteriorated.
During the protests in March, Bahraini authorities charged 24 doctors and 23 nurses from Manama's central Salmaniya hospital with incitement to overthrow the regime.
Meanwhile, the opposition Islamic National Accord Association called for a mass protest on Friday.
The demands include an elected government,a parliament with teeth and equitable division of electoral constituencies.