OPP say a minivan hit a horse and buggy on Road 92 in Zorra Township shortly after 10 a.m. on Wednesday, injuring four people.
Emergency crews responded to the scene south of St. Marys and three children and an adult male in the buggy were transported to hospital.
Two boys, ages two and six, and a nine-year-old girl, are reportedly in serious but stable condition.
The 41-year-old old man, the children's father, is also in stable condition.
OPP Const. Ed Sanchuk says the driver of the van, an 84-year-old male, was not injured.
The horse was injured and transported to a local farming property, but will not need to be put down due to its injuries.
Sanchuk added that it appears both vehicles were eastbound on Road 92 when the van rear-ended the buggy, ejecting one of the children from the buggy.
Road 92 was closed from 15th Line to 19th Line until almost 3 p.m .as police investigated the collision and the area was cleaned up.
The driver of the minivan from Oxford County has been charged with careless driving.