Filtering rules in effect at

For each set of filtering rules, we provide them in raw text and also in an graphic form. Thanks to Mattias Rarey and his group for SMARTSviewer.

Basic filters: applied to all vendor catalogs

Annotated catalog filters

Catalogs of biologically active molecules are filtered using more permissive rules (because they are active).

Secondary filters

Molecules are annotated as potentially problematic if they match any of these filters.

yuck rules

The "clean" subsets in ZINC have any molecule matching any of these two yuck rule sets filtered out.
Editorial comment: We do not endorse either set of yuck rules. They are provided merely as a convenience to users. Many perfectly good actives and over 1/2 of purchasable chemistry are filtered out by these rules. caveat emptor

yuck1 rules

A second set of rules.

Blaster rules

During upload and DOCK Blaster, we are more tolerant of ligands since they bind (i.e. in the PDB).
These are like the rules for Many thanks to David M. Lorber for the filtering script and our colleagues for advice. As always at, the sole responsibility for any errors is John Irwin's.
Finally, a wide range of SMARTS definitions. Last updated: October 2011.