In the field of pharmacy, compounding is preparation of custom medications to fit unique needs of patients that cannot be met with mass-produced products. This may be done, for example, to provide medication in a form easier for a given patient to ingest, or to avoid a non-active ingredient a patient is allergic to, or to provide an exact dose that isn't otherwise available. This kind of patient-specific compounding, according to a prescriber's specifications, is referred to as "traditional" compounding. The nature of patient need for such customization can range from absolute necessity to individual optimality to even preference.