Jair Bolsonaro said in an interview that he lost his memory for a short period of time.
"I had partial memory loss. This morning I managed to recover a lot of stuff. Now I am fine. I did not know, for example, what I had done in the previous day", he told the Band TV network.
The statement comes after the Brazilian president's office said that Bolsonaro had spent the night at the Armed Forces Hospital in Brasilia under observation and was released on 24 December "with the recommendation that he rest".
The president said that he slipped and fell on his back in his bathroom.
"It was a nasty enough blow but I'm going to take care of myself", Bolsonaro said in the interview.
Brazil's head of state also recently underwent a biopsy to detect signs of skin cancer at the Armed Forces Hospital in Brasilia after noticing an ear wound. However, the biopsy did not report the presence of the disease.