A molecular reversion field was a spatial anomaly that could interfere with transporter patterns and the molecular structures of objects passing through it.

In 2369, the shuttlecraft Fermi was trapped in and destroyed by such a field. Traveling aboard the shuttle were Captain Jean-Luc Picard, Ensign Ro Laren, Keiko O'Brien, and Guinan. As the shuttle began to break up, the USS Enterprise-D attempted to beam them off the shuttle. The molecular reversion field obscured portions of their patterns, in particular the ribo-viroxic-nucleic structure of their DNA, and the transporter re-materialized all four without it. (TNG: "Rascals")