CSU General Secretary Stephan Mayer has resigned after only a short term in office.
"For health reasons, I asked the party leader of the CSU today to release me from my job as general secretary," Mayer said in a statement distributed by the CSU on Tuesday.
The "Bild" newspaper had previously reported on it.
Mayer had come under heavy pressure because of allegations by Burda Verlag.
The publisher accused the CSU general secretary of massively threatening and blackmailing a reporter.
According to the "Bild" newspaper, a three-page letter from the publisher's lawyers said that Mayer had threatened a journalist from the "Bunte" magazine, which belongs to Burda-Verlag, with personal destruction.
As the newspaper writes, Mayer also referred to this in his statement.
He wrote: "In a conversation with a Bunten journalist, which was based on blatantly unlawful reporting, I may have used a choice of words that, in retrospect, I would not consider appropriate.
I very much regret this.”
Party leader Markus Söder only announced at the end of February that Mayer should succeed Markus Blume as Secretary General, and thus caused a surprise in his own ranks.
The 48-year-old lawyer Mayer was elected to the Bundestag in 2002 and distinguished himself as an expert with liberal-conservative positions.