The Oscar-winning actor, 76, said the public needed to see the US President “humiliated”.
The Irishman star and long-standing Trump critic made the remarks during an appearance on documentary maker Michael Moore’s podcast.
De Niro said: “I’d like to see a bag of s*** right in his face. Hit him right in the face like that and let the picture go all over the world.
“That would be the most humiliating thing because he needs to be humiliated. He needs to be confronted and humiliated by whoever his opponent is – his political opponent.