The fertilizer-laden truck carrying a group of 10 pilgrims overturned after the driver lost control over the vehicle, Superintendent of Police Varun Kumar Sinha said.
The pilgrims were returning to their native village after taking dip in the river Ganga at Simaria ghat in neighbouring Begusarai district on the occasion of Kartik Purnima.
The dead were identified as Amirkaa Devi (50) Suryamukhi Devi (52), Ganga Devi (48), Seema Devi (46) - residents of Banda Basaut village, Sinha said.
The injured were admitted to the nearby Primary Health Centre (PHC) where they were administered first aid and discharged, the SP said.