Firefighters had to cut the roof off a car to release an injured woman after a three-vehicle crash.
Once free, the woman was taken to Stoke Mandeville Hospital for treatment.
She suffered suspected spinal injuries but they not thought to be serious.
Another woman and a man, who were both injured, and a third woman, who was uninjured, were freed before firefighters arrived.
One of the injured pair was taken to Stoke Mandeville Hospital with chest injuries.
The incident happened yesterday at around 7.35pm in London Road.
Two fire crews from Aylesbury attended the crash.
The road was closed until 9.18pm.
Aston Clinton resident Simon Icke said: “The whole road was closed and there were at least two fire engines and police cars.
“It was cordoned off, it was obvious it was a major accident.
“A car had its roof cut off. There was a foreign number plate on one of the cars.
“What seemed to be strange was that there was no diversion in place. I couldn’t understand why the traffic wasn’t being stopped further up.
“Most people drove right up to the scene of the accident and than had to turn around. The road was closed for more than two hours.”