National Highways reported shortly after 8am that lanes one and two of the southbound carriageway were closed between Junction 5, Droitwich, and Junction 6, Worcester, due to the crash.
Initially two lanes were closed, but this was increased to three to allow for the recovery of the caravan.
The agency warned drivers shortly before 9am that delay times had reached 25 minutes with four miles of queues.
At 9.25am the agency reported that all lanes had been reopened, but still warned of long delays.
"Please allow extra time if travelling in the area as delays of 40 minutes and approximately four miles of congestion remain."
