Damage Over Time (DoT) is an offensive ability offered by the Pharmakon. In particular, dealing damage will apply DoT Stacks to the target. Each DoT Stack inflicts damage at set intervals for a relatively long duration.
Whenever a ship with the DoT ability deals damage to an enemy ship or module equal to the Damage Threshold (in terms of health damage after resistances), that enemy receives the specified number of DoT Stacks. This part is very similar to that of Ablation.
Unlike Ablation, the counter for DoT Damage Threshold is separate for each enemy. For example, given that the Damage Threshold is 250, a ship dealing 249 damage to each enemy would not apply any DoT Stacks. However, if the same ship deals 1 more point of damage on any enemy, that same enemy would immediately receive DoT Stacks.
Note that DoT is an intrinsic ability of Pharmakon Hulls; it is not necessary to have Pharmakon Ship Weapons or those that grant DoT Stacks in order to make use of this ability. In the same vein, other hulls are unable to inflict DoT even if they use such weapons.