Absence Makes the Heart Grow Fungus is an instrumental record by Omar Rodríguez-López released by Infrasonic Sound. It is one of four solo albums completed in 2001 by Omar Rodríguez-López during the interim period following the demise of At the Drive-In and the formation of The Mars Volta. Absence was tracked at Doug Messenger's North Hollywood studio only a few weeks after Rodriguez-Lopez recorded A Manual Dexterity Soundtrack, Vol. 1 there, and is comparable to that project in both sound and atmosphere. The album features tracks that were "originally intended for use by The Mars Volta." No personnel credits are listed in the insert for either the LP or CD, though it features a photograph of Jeremy Michael Ward never seen prior to this release.
The song "Hands Tied to the Roots of a Hemorrhage" is the foundation of what would become "Eriatarka" on The Mars Volta's first full-length, De-loused in the Comatorium. Also, the song "Teflon" from TMV's 2009 album Octahedron includes parts worked from the song "A Story Teeth Rotted For".