A man is believed to have been stabbed in Monson Street, off Lincoln High Street.
Witnesses say the man was stabbed in the arm after an argument in the street at around 6:30pm this evening.
Taxi drivers at Discount Cabs say the man then entered the office to order a taxi to the hospital.
The emergency services were then called and police closed the road to close off the crime scene.
The man was treated in the taxi office and then taken to hospital.
Monson Street was re-opened at around 7:30pm but there is still a police presence in the area.
The police are yet to confirm the incident.
David Cookson volunteer LIVES doctor Tweeted: "Attended stabbing in central Lincoln, supporting EMAS NHS Trust and Lincs Police - great communication and teamwork on scene.