Three fire crews responded to the crash between Junction 6 for the A38(M) and Junction 7 at Great Barr, on the northbound carriageway, at around 11pm working to clear debris and make the cars safe while the road was closed.
Details of any injuries are not yet known.
A spokeswoman for West Midlands Fire Service said: "We got the call at 10.54pm. It was one car that had hit the central reservation.
"We sent two crews to the scene and one to the other carriageway. No one was trapped.
"There were several other cars that got damaged so there was a lot of debris on the carriageway.
"It was closed for a short time to make the road clear.
"We left the scene at 11.46pm after making the vehicles safe. A total of seven cars suffered damage."
The road was reopened early on Saturday morning.
Meanwhile the M6 is closed further north at Junction 10 in Walsall this weekend while a new bridge is installed.
Drivers are facing long delays due to the work, part of a £78 million scheme to reduce congestion through the Black Country.
The motorway will be closed at this junction until Monday morning.
Traffic is being diverted off the carriageway at the exit slip road, up and over the junction and then back onto the motorway while 44 metre-long steel bridge beams weighing up to 120 tonnes are lowered into place.
Motorists are being urged to avoid the area this weekend.