**3. Conclusion**

In battling against various diseases and emergence of drug resistance, the use of two drugs in combination that have different modes of action greatly reduces the likelihood of the emergence of a drug-resistant strain. The higher the synergy the less the amount of each drug is required because less than 50% of each constituent should be able to achieve 100% treatment rates when synergy is found in a given combination [54]. Therefore, doses of drugs will be lower and thereby leading to much better dosing regimens, high tolerability, and safety [19, 55].

Synergism is distinctive in phytotherapy with the use of ginger in traditional medicine being efficacious and safe with no side effects [17]. Therefore, as epidemiological studies continue to report increased spread of various diseases and emergence of drug resistance, these factors argue for use of herbal-herbal combinations and herbal-drug combinations. In such combinations, numerous phytochemicals act in a useful manner and the activity is enhanced through synergism contrary to the use of synthetic pharmaceuticals that rely on one active ingredient [13]. This explains the

increased popularity of herbal medication, especially when used in combination as is the case with phytochemical activities of ginger combinations.

Most of the pharmacological activities of ginger combinations have shown synergism conferred by its phytochemical components. The highest synergism was observed when phytochemicals isolated from ginger, gingerol, and shogaol derivatives were combined and tested against prostate cancer cell lines with an IC50 value of 0.03. Such synergistic interactions are vital in phytomedicine in overcoming the challenges of isolating active ingredients in medicinal plants since whole or partially purified extracts show efficacy in low doses [13]. These studies depict that ginger potentiates standard drugs, pure compounds, or other plant extracts when used in combination. Therefore, *in vivo* studies of ginger combinations and the mode of action are highly recommended as most of the ginger combination studies did not report on these aspects.
