The confrontation broke out as pupils were being dropped off at Broomhouse Primary School and horrified staff watched the pair “roll around the ground” as punches flew.
It is understood a 43-year-old mother – a member of the parent council – lunged at a woman, 27, who was marching to the principal’s office to report “disparaging comments” made about her child on social media.
The younger parent is then said to have dragged the other mother along the ground of the reception area delivering several blows that left her “covered in blood” and in need of hospital treatment.
School staff – including the headteacher – pleaded with the women to calm down and stop fighting.
One parent, who asked not to be named, said: “It happened in the main reception of the school, just before 9am.
“It was two mothers of children in the same class. One of the women has a girl at the school - the other one, she’s on the parent council, just lunged at her.
“The older woman was left with facial injuries and bruising. A little girl was physically sick. Everyone was just screaming, ‘stop, stop!’ The head teacher was white as a sheet. We were shocked.”
Another source told how the pair “exchanged words” before going toe-to-toe and wrestling each other to the floor.
The older of the two hot-tempered women required hospital treatment for facial injuries and bruises, the Evening News understands.
The incident occurred shortly after the morning run last Wednesday.
It is thought the parents met by chance in the reception area of the school as complaints were set to be made about the comments and conduct of one on social media.
Parent council leaders declined to comment on the brawl.
Police confirmed that both women have been charged in connection with the fight and ordered to attend court.
A spokeswoman said: “Police Scotland attended an incident at around 9am at Broomhouse Primary School on Wednesday, following an altercation between two parents.
“A 27-year-old woman has been charged with assault and a 43-year-old woman has been charged with a breach of the peace. They will both appear in court at a later date.”
Education bosses said they were working with police officers to resolve the situation.
A spokesman for Edinburgh City Council said: “We are aware of an incident at the school on Wednesday and are liaising with the police.”
Ambulance crews confirmed they were called to Broomhouse Primary and said one individual needed hospital treatment for injuries described as “minor”.
It is not yet known when the duo will appear at Edinburgh Sheriff Court.