The M3 has been closed northbound between Junction 6 (Basingstoke) and Junction 5 A287 (Hook).
The closure has cause congestion back to Junction 7 (Basingstoke) and also on the A30 London Road.
The details surrounding the medical emergency remain unknown at this time.
However, Hampshire police said: ‘We’re dealing with a serious injury incident on the M3 northbound at Junction 5. Two lanes are closed leading from Junction 6 to 5, in addition the off-slip at Junction 5 and the on-slip at Junction 6 are closed. Please consider other routes before travelling.’