Combination therapy or polytherapy is therapy that uses more than one medication to treat a disease or disorder.
Combination therapy or polytherapy is therapy that uses more than one medication or modality (versus monotherapy, which is any therapy taken alone). Typically, these terms refer to using multiple therapies to treat a single disease, and often all the therapies are pharmaceutical (although it can also involve non-medical therapy, such as the combination of medications and talk therapy to treat depression). 'Pharmaceutical' combination therapy may be achieved by prescribing/administering separate drugs, or, where available, dosage forms that contain more than one active ingredient (such as fixed-dose combinations).
Polypharmacy is a related term, referring to the use of multiple medications (without regard to whether they are for the same or separate conditions/diseases). Sometimes "polymedicine" is used to refer to pharmaceutical combination therapy. Most of these kinds of terms lack a universally consistent definition, so caution and clarification are often advisable.