lwreg does not directly support performing chemical searches like similarity or substructure searches. However, users wishing to do chemical searches on their lwreg tables can install either the RDKit's PostgreSQL cartridge or Riccardo Vianello's chemicalite cartridge for sqlite . Because this is not part of lwreg itself and installing and configuring either of these database add-ons can be non-trivial and specific to a particular database deployment, we only highlight the possibility for this integration here and will not go into detail.