A 40-year-old woman suffered serious injuries and had to be cut free from a camper van after it hit a group of loose horses in East Sussex.
One of the five horses was put down by a vet and two more were treated for their injuries after the accident on the A26 at Clayhill early on Tuesday.
The injured woman was taken to the Royal Sussex County Hospital.
The 48-year-old male driver of the van, from Uckfield, and a 44-year-old male passenger were also injured.
They were also taken to hospital, but police said all the injured were expected to make a full recovery.
Two children in the van were unhurt in the accident but were taken to the Royal Sussex County Hospital to be checked over.
Police are appealing for anyone who saw the crash, or the horses in the area beforehand, to come forward.