Tinctures are alcoholic extracts of herbs, which are generally stronger than herbal teas. Heavy metals are thought of as active ingredients by advocates of Indian herbal medicinal products. Cornflowers are often used as an ingredient in some tea blends and herbal teas. These include diets, probiotics, fish oil and other herbal and nutritional supplements. Many chemical agents, including medications, industrial toxins, and herbal and dietary supplements, can cause hepatitis. The country maintains a vibrant tradition of herbal and medicinal practices. Many roses have been used in herbal and folk medicines. Chinese privet is used in traditional herbal medicine. These and others were traditional as topical treatments for localised skin cancers in herbal medicine. Roman physicians used a wide range of herbal and other medicines. Only limited evidence exists for the effectiveness of other herbal remedies for IBS. Hops are also used for various purposes in other beverages and herbal medicine. It is used as a flavouring in food and herbal teas. Lavender flowers are occasionally blended with black, green, or herbal teas. Many Hmong still follow the tradition of taking herbal remedies.