Herbal medicine. View of a tray full of various plants used in herbal medicine. The pink flowering plant at lower centre is a foxglove (Digitalis sp.) which contains the extract digitalis. This contains two substances, namely digitoxin and digoxin, these stimulate the heart muscle. The periwinkle (Vinca sp., at centre right) is a source of alkaloids, used to treat cancer. Also seen at bottom left is a stem of ginger (Zingiber officinale), a garlic clove (Allium sativium, bottom left) and a hawthorn (family Rosaceae) at top right. A pestle & mortar is at top left corner.