Herbal teas contain soluble polyphenols which impart astringent effects thought to have medicinal properties. Heavy metals are thought of as active ingredients by advocates of Indian herbal medicinal products. Machis often have extensive knowledge of regional medicinal herbs. The country maintains a vibrant tradition of herbal and medicinal practices. The Society publishes a series of books about natural remedies and medicinal herbs. Herbs have a variety of uses including culinary, medicinal, and in some cases, spiritual. Bhang is also part of many Ayurvedic medicinal preparations. Culpeper spent much time outdoors cataloguing hundreds of medicinal herbs. Recently insects have also gained attention as potential sources of drugs and other medicinal substances. Cannabis is a plant used in Australia for recreational and medicinal use. Growing there are rare and exotic medicinal and aromatic plants. A number of other plants (often poisonous, medicinal and/or psychoactive) are associated with Hecate. Thus, the term "medicinal" (instead of herb) is usually preferred. Apple cider vinegar has no medicinal or nutritional value. Pharmacopoeia standards for medicinal oils should be heeded.