Rumex brownii is a perennial to 1m tall, with oblong leaves and flowers in whorls on an open branched inflorescence. The valves have three to five hooked teeth on each side. It is considered a weed in gardens.
Plants can contain quite high levels of oxalic acid, which is what gives the leaves of many members of this genus an acid-lemon flavour. Perfectly alright in small quantities, the leaves should not be eaten in large amounts since the oxalic acid can lock-up other nutrients in the food, especially calcium, thus causing mineral deficiencies. The oxalic acid content will be reduced if the plant is cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition [Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995 ISBN 0-7513-020-31].