The Llanelli regional side scored their first bonus point of the season to cement second place in the League table, but four key forwards limped off the field in the process. Young scrum-half Mike Phillips was forced to play in the backrow for the final 15 minutes.
"To lose four forwards in a game is sod's law and it disrupted our overall performance," Scarlets boss Gareth Jenkins said.
"I don't yet know how expensive the injuries are going to be but we put a lot of good stuff together and I felt we missed an opportunity to score two or three more tries before halftime."
Dragons backrower Jason Forster was the toast of Rodney Parade on Saturday night as his two tries saw off a strong challenge from Edinburgh.
Forster scored in both halves and fly-half Craig Warlow added 19 points as the Dragons went from 10th to fifth on the table with a 34-22 win.
It was a miserable two hours for Welsh rugby on Friday night as all four Irish provinces notched up victories.
The Neath-Swansea region's awful Celtic League fortnight continued with a 22-33 loss at the hands of Connacht at St Helen's - the Ospreys' first home loss of the season - while the Cardiff Blues came back to earth with a thump, suffering a 7-32 reverse at table-toppers Ulster.
The Celtic Warriors copped a heart-breaking 21-22 loss at Munster thanks to a 79th-minute penalty goal to Jeremy Staunton and the Leinster Lions completed the Irish Grand Slam with a 31-10 win at Glasgow.