A bewildering variety of vegetation grows on the mountainsides of the Central Sierras and is representative of three of the country’s principal phytogeographic zones – the Andes, the Pampas and the Chaco. Many of these plant species are reputed to possess remarkable medicinal properties. Perhaps best known is the peperina, of which there are two varieties: Mintostachys verticillata and Satureja parvifolia (the latter often known as peperina de la sierra). Both are highly aromatic and extremely digestive but, in men, diminish sexual potency. The yerba del pollo (Alternanthera pungens), on the other hand, is a natural cure for flatulence, while ephedrine, a tonic for heart ailments, is extracted industrially from tramontana (Ephedra triandra), a broom-like bush found all over the highlands at altitudes of 800–1300m.
Anyone suffering from problems of the gall bladder might do well to drink an infusion of poleo (Lippia turbinata), a large shrub with silvery foliage and an unmistakeable aroma. Appropriately enough, since Santa Lucia is the patron saint of the blind, the flor de Santa Lucia (Commelina erecta), whose intense blue or lilac blooms carpet the ground to astonishing effect, exudes a sticky substance that can be used as effective eye drops. The cola de caballo (Equisetum giganteum) – or “horsetail” – is used to control arterial pressure thanks to its diuretic powers; its ribbed, rush-like stems grow alongside streams and are crowned with hairy filaments that give it its popular name. Whatever you do, however, steer clear of revienta caballos (Solanum eleagnifolium or S. sisymbrifolium), a distant relative of the deadly nightshade. Its pretty violet flowers give way to deceptively attractive yellow berries, but the whole plant is highly toxic.
Obviously, you should seek expert advice before putting natural cures to the test, and they should not be used instead of conventional medicine for the severest of complaints. Pharmaceutical herbs, known as yuyos, are sold (usually in dried form) in pharmacies and in stores selling dietetic products throughout the region.