The 80-year-old former head of state was transported from the National Penitentiary Institute (INPE) to a private clinic in Lima due to high blood pressure and abdominal pain, local media reported.
"Fujimori was discharged this morning and returned to the Barbadillo prison, after being hospitalized for more than 24 hours in the Centennial Clinic," RPP radio said.
According to his physician and the former Minister of Health, Alejandro Aguinaga, Fujimori underwent an endoscopy for hemorrhagic (erosive) gastritis Tuesday morning and was discharged later that afternoon, but will be required to begin treatment and a "strict follow-up schedule."
Past circumstances related to tongue cancer, various heart conditions, and hypertension have allowed him to leave his incarceration and seek medical treatment.
Fujimori was sentenced in 2007 to 25 years in prison for "mediating" the crimes in La Cantuta and Barrios Altos and the kidnapping of both a businessman and a journalist.
On December 2017, he was pardoned by former president Pedro Pablo Kuczynski, however, due to an irregularity in the process, the Judicial Power determined to revoke his pardon. He still has 13 years left on his sentence.