His coach Thomas Tuchel has been outspoken about what he perceives to be an excessively physical approach adopted by opposing teams this season, and Dembele appears to agree.
No Bundesliga side have been on the receiving end of as many fouls as BVB (291), while only league leaders Bayern Munich have conceded fewer than their 186.
"It is not normal for us to be the most fouled team, committing the fewest [second fewest] fouls, but still have so many yellow cards. I do not understand that," the Frenchman told Sport Bild.
"It annoys me that in the last five or six games, the opponents have looked to stop our flow with tactical fouls that go unpunished.
"I'd really like the referees to act earlier and harder.
"There are players who have fouled me five or six times in a game without getting a card, and when they do it's often very late.
"In the Champions League it is different; there is a card after at least the second or third tackle."
Dortmund return to Bundesliga action following the mid-season break in a trip to Werder Bremen on Saturday.