The four-time winners of the competition burst into life in the second half with tries from Thierry Dusautoir, Maxi Medard and Louis Picamoles.
Will Harries hit back with a try for the home side but it was not enough with Toulouse ’s dominant second half display putting the Dragons to the sword.
The win means they maintain their 100 per cent start to the competition and continue to set the pace in Pool Six.
In a tense first half the Men of Gwent matched Toulouse in almost every department. David Skrela and Matthew Jones, a late replacement to the starting line-up, exchanged a number of kicks.
Skrela was winning the kicking dual and edged the visitors into a 15-9 lead. But after 32 minutes he was sent to the sin-bin for interfering at the break down.
Jones punished his opposite number’s indiscipline and pull the Dragons back to within three points at the interval.
But Toulouse went up a gear in the second-half with and were soon nudged further in front by Skrela after the Dragons scrum began to creak.
Things got worse for the Welsh region as they struggled to cope with Toulouse’ intensity. And Dusautoir soon opened the scoring to give his side a commanding 28-12 lead.
Mid-way through the half, Toulouse grabbed a second try thanks to a sensational effort from Medard. But the Dragons continued to fight and hit back with a try from the electric Harries after a quick-tap from Steve Jones.
But that was as good as it got for the hosts as Picamoles crashed through the defence to score Toulouse ’s third try, secure the win and maintain their unbeaten record against the Newport-based region