The Deruga Case () is a 1938 German crime drama film directed by Fritz Peter Buch and starring Willy Birgel, Geraldine Katt and Dagny Servaes. It is based on the 1917 novel of the same title by Ricarda Huch. It was shot at the Babelsberg Studios in Potsdam. The film's sets were designed by the art directors Wilhelm Depenau and Ludwig Reiber.
Doctor Deruga is put on trial for murdering his wealthy ex-wife, Mingo Swieter, after curare is discovered in her body during a post-mortem. The prosecution, driven by his ex-wife's embittered cousin, Baroness Truschkowitz, argues that the impoverished doctor killed her to inherit a fortune. Deruga refuses to provide an alibi to protect the reputation of another woman, but his innocence is eventually proven when it is revealed his ex-wife actually committed suicide to end her suffering from a terminal illness. The doctor is acquitted, but remains haunted by the experience.