When I use a word . . . . Taking therapeutic care.

In healthcare there are different forms of taking care or taking precautions. When using a therapeutic intervention, one takes care by implementing it appropriately. When the appropriate intervention is pharmacological that means giving an appropriate formulation of a medication in an appropriate dosage regimen. If the intervention might cause harm, but the benefit:harm balance is favourable, one might do nothing apart from monitoring or one might introduce a preventive strategy, such as the use of mesna when giving an oxazaphosphorine such as cyclophosphamide. Vaccination and contraception are both examples of precautionary measures that have an excellent benefit:harm balance. But when the benefit:harm balance of an intervention is unfavourable the precaution to be taken is avoidance of the intervention. That, and only that, form of precaution, avoidance to avoid harm, is a defining feature of the precautionary principle.