Every drug included in DrugBank has its data curated on a specific drug card, or webpage. On each drug card there are sections pertaining to what targets, enzymes, carriers, and transporters that the card's drug interacts with. Every [bio entity] that is added to each of these sections is marked as either 'yes', 'no', or 'unknown' in a field titled 'pharmacological action'. A [bio entity] is marked as 'yes' for pharmacological action if the card's drug interacts directly with the [bio entity] as part of its mechanism of action. A [bio entity] is marked as 'no' if interaction with it is not directly involved in the drug's mechanism of action. Pharmacological action is marked as 'unknown' if currently there is no formal research or evidence to elucidate whether interaction with the [bio entity] is associated with the drug's mechanism of action at all.