Dr. Jeff Williamson of the Wake Forest School of Medicine in Winston-Salem, N.C., said in a letter dated Tuesday that, as leader of Angelou's medical team, he has ordered the 85-year-old to forego any travel for the next three to four weeks. The reason for Angelou's hospitalization was not disclosed.
The letter was sent to Angelou's representative's bureau, MacRae Speakers & Entertainment LLC.
Butler University in Indianapolis announced Angelou has canceled an appearance scheduled for Thursday after the school was notified by MacRae Speakers & Entertainment LLC.
Among Angelou's most acclaimed works is the 1969 autobiographical work "I Know why the Caged Bird Sings."
The Associated Press contributed to this report.
