Mol files (.mol) are a file format for storing molecular structure data, which can be used by viewer programs to display a three dimensional rotating model of a given molecule. There are numerous software packages that can load and display .mol files. Erowid recommends the use of Jmol, an open-source Java viewer for chemical structures in 3D.

On the Erowid website, the Jmol applet is embedded in 3D Chem Compare and in each of the individual MOL pages listed on the Chemical Structures page. You need to turn on Java in your browser to make this work.