Pele has thanked well-wishers for sending "good vibes" after confirming his hospital stay was a routine visit.
Concerns were raised on Wednesday when ESPN Brasil reported Pele had been admitted to Sao Paulo's Hospital Albert Einstein with "general swelling".
The Brazil legend had a tumour removed from his colon in September 2021 and has since had regular treatment.
"Friends, I am at the hospital making my monthly visit," the 82-year-old wrote on Instagram.
The three-time World Cup winner included an image of a tribute to him at the Qatar World Cup alongside the post.
And he added: "It's always nice to receive positive messages like this. Thanks to Qatar for this tribute, and to everyone who sends me good vibes!"
ESPN Brasil also reported Pele was having cardiac issues and there were concerns that his chemotherapy treatment is not having the expected effect.
His daughter, Kely Nascimento, was moved to clarify on Instagram, saying: "There is no emergency or new dire prediction. He is in the hospital regulating medication."
Pele is Brazil's all-time leading scorer with 77 goals in 92 games, and the former striker is one of only four players to have scored in four World Cup tournaments.