Forty passengers suffered various degrees of injuries when a bus veered off the road and landed in a ditch near Kapkwen trading centre in Bomet County.
The Classic Coach bus was heading from Nairobi to Kisii on Sunday evening.
Eight of the injured passengers were rushed to Tenwek hospital.
Bomet Central sub county Police Commander Musa Imamai confirmed the incident, saying 32 other passengers with minor injuries were treated and discharged from the hospital.
“The bus is said to have swerved to avoid a head-on collision with a motor vehicle that was travelling towards Bomet from Kaplong when the accident occurred. The bus overturned and landed on its side,” Mr Imamai said.
“Some of the [passengers] had cuts from broken glass, while others had bruises in various parts of the body. A few others are still undergoing observation, but I think they will be discharged in due course,” said a doctor, who did not want to be named because he did not have the authority to speak to reporters.
Mr Stanley Mutai, a Bomet County senior disaster management officer, said the accident occurred at around 4pm.
Passengers who escaped without injuries were stranded at the scene of the accident for several hours and braved rain as they waited for alternative transport to their destinations.
Members of the public, motorists and county disaster management workers took part in rescuing passengers.
The area has been the scene of accidents before, with residents urging the Kenya National Highway Authority (Kenha) to erect pumps there so as to slow down motorists.
The wreckage of the bus was towed to the Bomet Police Station in an operation that lasted almost an hour, causing a traffic snarl-up on the Bomet-Kisii highway.