A further five people were taken to hospital with milder injuries and suffering from shock.
The emergency services were called to the incident at 5.52pm. The accident happened as a car turned into Boråsvägen from a minor road, crashing into another car which was travelling eastwards.
At the same time, a third car, which was travelling west, collided with the first two.
The cars burst into flames, prompting a major rescue effort. As well as eight ambulances, the emergency services sent five cars to the scene and flew in a medical team by helicopter.
Rescuers were able to cut two people out of the burning cars.
In total, seven people were taken by ambulance and helicopter to Sahlgrenska and Östra hospitals in Gothenburg.
Police say they will investigate whether the accident was caused by carelessness on the part of any of the drivers involved.