It is a parody of the Robert Louis Stevenson's 1886 novella Strange Case of Dr Jekyll and Mr Hyde.

A detective later discovers this is happening and frees Floria from his kidnapper while the Professor's mind ends up within the body of a monkey at a zoo.

[1] [2] My Friend, Dr. Jekyll was released in Italy on August 11, 1960 where it was distributed by Incei Film.

[1] It grossed a total of 157 million Italian Lira on its initial theatrical run.

[1][3] The film was acquired by Dick Randall through the purchase of Sam Fleishmann's shares in the company.