Ephedrine powder is a naturally occurring central nervous system (CNS) stimulant derived from the Ephedra equistina plant. Ephedrine powder is available in the US as an over-the-counter medication for the relief of breathing problems. It is rarely used because there are safer ephedrine powder products available for purchase online. Ephedrine powder is a decongestant and bronchodilator. It works by reducing swelling and constricting blood vessels in the nasal passages, thus widening the airways in the lungs and allowing you to breathe more easily.