Ephedra or Ma-huang(Ephedra sineca): Ephedra is a medicinal plant that has been cultivated for over five thousand years in China, where it was used for asthma and hay fever-like conditions. Also known as ma-huang, the stems contain two primary alkaloids, ephedrine and pseudoephedrine, which are now approved for use in over-the-counter decongestant and bronchial drugs. Ephedrine has a marked peripheral vasoconstricting (causing constriction of the blood vessels) action. Pseudoephedrine is a bronchodilator (able to dilate the windpipe), approved for use in asthma and certain allergy medicines. Ma-huang and its extracts are found in a number of herbal formulas that are designed to increase energy and reduce appetite. Both ephedrine and pseudoephedrine have central nervous system (CNS)-stimulating properties, ephedrine being more active. The CNS activity of these alkaloids has been characterized as being stronger than caffeine and weaker than methamphetamine (a central nervous system stimulant). Hence, as is the case with caffeine, this herb should be used with caution or avoided by those with high blood pressure, diabetes, glaucoma, and related conditions where hypertensives are contraindicated.