There are roughly 13,000 medicinals used in China and over 100,000 medicinal recipes recorded in the ancient literature. Plant elements and extracts are by far the most common elements used. In the classic "Handbook of Traditional Drugs" from 1941, 517 drugs were listed – out of these, only 45 were animal parts, and 30 were minerals. For many plants used as medicinals, detailed instructions have been handed down not only regarding the locations and areas where they grow best, but also regarding the best timing of planting and harvesting them.