The flames broke out just after Midnight on Monday at in the flat on Craiagentinny Road in Edinburgh.
A 43-year-old woman and her 16-year-old son were taken to hospital to be treated for smoke inhalation.
The 68-year-old neighbour and a 30-year-old man were also treated on scene.
A Lothian and Borders Fire and Rescue Service spokeswoman said: “The fire was contained in the kitchen area. We used four breathing apparatus and one high pressure hose reel.
“One 68-year-old neighbour suffered smoke inhalation trying to assist.
“A 43-year-old female and a 16-year-old and a 30-year-old, both male, suffered smoke inhalation and were treated with oxygen therapy.
“They were seen by the ambulance crews.”
A Scottish Ambulance Service spokeswoman said: “We received a call about 00:30 from the fire brigade.
“A mother and son were treated for smoke inhalation and were taken to hospital.
“A third person was checked but was fine and didn’t travel to hospital.”
The fire was the fourth Lothian and Borders Fire and Rescue had to attend throughout the course of Sunday night.
Earlier, just before 6pm a fire broke out in the living room of a home in Laburnum Road, Whitburn in Bathgate.
A 55-year-old woman was rescued from the house.
A spokeswoman for Lothian and Borders Fire and Rescue said: “A fire started in living room of house.”
“It was extinguished prior to the fire service attending.
“A 55-year-old female was treated on the scene and refused to go to hospital.”
And at around 7pm a fire broke out in the kitchen of a first floor flat in Grange Loan in Edinburgh.
A 23-year-old man suffered smoke inhalation but refused to go to hospital.
A fire service spokeswoman said: “A high pressure hose reel was used to extinguish the fire as well as a breathing apparatus.
“One 23-year-old male suffering from smoke inhalation received treatment from ambulance crews but didn’t require to go to hospital.”
Then at 10.30pm the fire service were alerted to a fire in Scott Street in Galashiels after a pan of food burst into flames.
A member of the retained fire crews raised the alarm when he heard a smoke alarm while out walking his dog.
Members of the retained fire crews are required to carry alerters at all times.
A fire and rescue spokeswoman said: “It was caused by a pan of food alight which was extinguished on our arrival
“A 23-year-old man was checked over by the ambulance but didn’t require to go to hospital.”
A Scottish Ambulance Service spokeswoman said: “We received a call at 22:40 from the fire brigade.
“A 23-year-old male refused any treatment.”
