Though often overlooked, many medicinal plants contain useful levels of vitamins. Some are well known for their vitamin content, for example dog rose (Rosa canina, p. 263) has high levels of vitamin C, and carrot (Daucus carota, p. 201) is rich in betacarotene (pro-vitamin A), but many are less well recognized. Watercress (Nasturtium officinale, p. 239), for example, contains appreciable levels of vitamins B1, B2, C and E as well as beta-carotene, while sea buckthorn (Hippophae rhamnoides, p. 220) can be regarded as a vitamin and mineral supplement in its own right.