Issue #1 of the new ongoing series will be part of the promotional day.
The last two years have seen the debut of the publisher's ongoing titles Spontaneous and The Sixth Gun.
Writers Nunzio DeFilippis and Christina Weir (Batman Confidential) and artist Christopher Mitten (Criminal Macabre) are working on the series, which centres around a doctor working on the very fringes of medical science.
"This is not a zero issue, it's not a preview or an advanced look, this is the actual issue #1 of Bad Medicine," said marketing director Cori Casoni.
"At Oni Press, we believe that Free Comic Book Day is about free comics. By launching a brand new series on FCBD, we're creating a no-risk situation for new readers to try out a new monthly comic book, and the best part is, they only have to wait a few weeks to read the next instalment!"
Free Comic Book Day will be held on Saturday, May 5.
A retailer edition of Bad Medicine #1 will be released alongside issue #2 on June 12.
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