(R)-(-)-Phenylephrine hydrochloride is primarily used as a decongestant in over-the-counter and prescription medications to relieve nasal congestion caused by colds, allergies, or sinusitis. It works by constricting blood vessels in the nasal passages, reducing swelling and making breathing easier. Additionally, it is employed in ophthalmic solutions to dilate the pupil during eye examinations or surgeries. In some cases, it is also used to treat low blood pressure, particularly in surgical or emergency settings, by increasing blood pressure through vasoconstriction. Its applications extend to certain formulations for hemorrhoid relief, where it helps reduce swelling and discomfort.