Gladbach are 16th in the standings on one point, their poor run extending to 10 league games without a win, including last season.
"After an intensive review of our start to the season, we have come to the conclusion that we have to make a change in the position of head coach," Gladbach Sporting Director Roland Virkus said in a statement.
"After 10 Bundesliga games without a win, we have lost faith that the turnaround with Gerardo can succeed."
Swiss Seoane, who took charge of the five-time Bundesliga champions in 2023, will be replaced on a temporary basis by Gladbach's Under-23 coach Eugen Polanski.