It happened in the westbound lanes of the 10 Freeway at Citrus Avenue around 11:20 a.m.
Eventually, the truck was removed, but syrup was still oozing across the mainlanes of the freeway.
AIR7 flew above the scene, where a major backup extended more than five miles to the east -- all the way to Colton -- after all westbound lanes were closed. Traffic was being directed off the freeway at Citrus Avenue.
Caltrans crews worked diligently to clean up the sticky situation. They first laid down absorbent material in an attempt to sweep it up, but when that didn't work, they brought in a water truck to hose it down and vacuum it up.
In the end, the westbound lanes were closed for nearly nine hours, making for an all-day traffic headache for drivers in the area. All westbound lanes were reopened at 8 p.m.
It's unclear what led to the semi-truck overturning at the on-ramp.