Otherwise, many programs that claim to be able to import Encapsulated PostScript (EPS) files really can only place them. Versions of Illustrator before 7.0 fall into this category. It will accept an EPS file generated by ChemDraw or Chem3D as a black box, but will not allow you to edit it. Many other programs also fall into this category, including Adobe Photoshop and Corel Draw. These programs can only edit a certain class of EPS files that contain a small subset of legitimate PostScript commands. In contrast, PostScript laser printers understand all PostScript commands, that is why ChemDraw and Chem3D graphics print so well. To load ChemDraw and Chem3D graphics into Illustrator so that you can edit them, you will first need to convert them into a format that Illustrator can understand. One way to do this is to use the Adobe Acrobat Distiller, which is included free with recent versions of Illustrator and Photoshop (look on the CD-ROM that comes with those packages). On the Macintosh, there is also the shareware epsConverter, which does an excellent job. The resulting files after conversion will often be much larger than the original ChemDraw or Chem3D EPS files (sometimes by a factor of 1000), but they will be able to be edited in programs such as Adobe Illustrator. Source.