At around 3.10 in the morning on Monday, emergency services were called to a collision on the A737 near Howwood involving a Mercedes A-Class sedan and a MAN box van.
Six horses were also reported to be running loose on the road at the time, according to several reports received by Police Scotland.
The Mercedes’s passenger, a 59-year-old woman, was declared dead at the site.
The driver of the automobile, a man 52-year-old, was taken to Queen Elizabeth University Hospital in Glasgow, while the passenger, a male 33-year-old, was transferred to Royal Alexandra Hospital (RAH) in Paisley.
The van’s 59-year-old male driver was also sent to the RAH for evaluation.
Four of the horses perished, according to Police Scotland.
“We are providing support to the family of the woman who died as our enquiries continue to establish the full circumstances of this crash,” stated Sergeant Jack Swindells.
“We would like to make an appeal to anyone who was traveling on the A737 on Monday morning at the time of the collision and who either saw the horses racing across the road or witnessed the tragedy occur.
“We also ask that anyone who has dashcam footage get in touch with us as soon as possible.”