Citing health concerns, the president of the National Organization for Women stepped down Sunday, amid a flurry of allegations of racism at the nation’s oldest and largest feminist organization.

In an email to the NOW board, state presidents, and staff on Sunday night, President Toni Van Pelt announced she would be stepping down with two weeks’ notice effective Aug. 28. Vice President Christian Nunes will take her place, and the board will begin the process of appointing a new vice president.

In her email, Van Pelt said she had been struggling with a “very painful health issue” over the last year and that her doctor had “implored me for months to stop working.”

“I have been ignoring my doctor’s advice and my health for too long, so I have made the very hard decision to retire and step down as President of NOW,” she wrote.

Van Pelt’s resignation comes on the heels of an internal investigation into allegations of racism and a toxic work environment at the storied feminist group. Ten minutes after Van Pelt’s resignation email, the same group of NOW leaders received an email saying the internal investigation had uncovered “governance issues and evidence of a toxic work environment.” Allegations of racial discrimination and retaliation, the email said, were not substantiated.