The incident occurred at 5 pm on Sunday and started on road 508 / Björkenäsvägen.
The police followed the car and shortly afterwards, at the Mörrum västra junction, the car drove off the road and overturned.
Emergency services and an ambulance were called to the scene.
Both people traveling in the car were taken to hospital with unclear injuries.
The motorist, a man in his 20s, is now suspected of several crimes: drug driving, illegal driving, negligence in traffic and causing bodily injury.
The passenger was a 15-year-old boy and he is not suspected of any crime.