McDonald's drive-thru at Brundall was shut as the air ambulance went to the aid of a driver who suffered a medical episode.
Police were called to the petrol station near the restaurant at just before 2pm on Saturday.
Two vehicles were involved in the crash, with one of the vehicles crashing into another one and into a hedge.
A white Audi and a black MG ZR were involved.
Police said the driver of one of the vehicles had passed out during a 'medical episode'.
Witnesses said the air ambulance landed on fields nearby.
The drive-thru was closed for several hours while emergency services deal with the incident.
It reopened by 8pm, and McDonald's tweeted: 'Our best wishes and speedy recovery to those hurt.'
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here