The case -- which has attracted international attention -- involves 20 doctors and nurses convicted of weapons possession, inciting sectarian anger and hatred of the regime, obstructing the law, destroying public property, jeopardizing general security and forcefully occupying the Manama medical complex where they worked.
The medics have argued they were just trying to do their jobs by treating the demonstrators brought into Salmaniya Medical Complex.
Bahrain's foreign minister, Khalid al-Khalifa, promised a complete retrial after Physicians for Human Rights claimed the medics were tortured in captivity.
The appeal court will "initiate a new trial and all the evidence and testimony will [be] re-examined and will be retested," the group said al-Khalifa told them.
Some of the convicted medical personnel told New York-based Human Rights Watch they endured electrocution, beatings, solitary confinement, lack of food and water, sexual harassment, 12-hour interrogations and weeks of detention without being able to speak to lawyers.
United Nations Secretary General Ban Ki-Moon said the five- to 10-year sentences the medical personnel received were "harsh" and raised "serious questions of due process irregularities," The New York Times reported.