In parts of India, Sri Lanka, and southern China, areca nuts are not only chewed along with betel leaf, but are also used in the preparation of Ayurvedic and traditional Chinese medicines. Powdered areca nut is used as a constituent in some dentifrices. Other traditional uses include the removal of tapeworms and other intestinal parasites by swallowing a few teaspoons of powdered areca nut, drunk as a decoction, or by taking tablets containing the extracted alkaloids. According to traditional Ayurvedic medicine, chewing areca nut and betel leaf is a good remedy against bad breath. Diplomat Edmund Roberts noted that Chinese people would mix areca nut with "Uncaria gambir" during his visit to China in the 1830s. After chewing a betelnut, the red residue is generally spat out. Accordingly, places have banned chewing this nut to avoid eyesores.