Abstract: The drug Xuan-fu-hua has long been used in traditional Chinese medicine and is included in the Chinese Pharmacopoeia 1977 as an expectorant and antivomiting agent. The botanical source as stated in the Pharmacopoeia is the dried flower-head of Inula japonica Thunb., family Compositae.Through a critical study of the descriptions of Xuan-fu-hua in the ancient Chinese herbals, it may be concluded that the botanical source of this drug should be Inula japonica Thunb. and I. britannica L.A survey of the botanical origin of this drug, however, revealed that the flowerheads of seven Compositous plants, viz. Inula japonica Thunb., I. britannica L., I. linariifolia Turcz., I. helianthus-aquatica C. Y. Wu ex Ling, I. hupehensis(Ling) Ling, I. salicina L. and Anisopappus chinensis Hook. et Arn., are now in use in different districts of China. Among these, the drug derived from Inula linariifolia Turcz. is said to be able to cause irritant effects. It is, therefore, necessary to find means for identifications of the drugs derived from different sources. Botanically authenticated specimens of the flower-heads of the above seven species were collected and their morphological and histological characters compared.In this paper, descriptions of morphological and histologicai characters of the drugs are given and illustrated with line-drawings. A key for identification is also included.The results showed that the morphological and histological characters of flowerheads of the six species of Inula are rather similar. It is, therefore, in accordance with their taxonomical relationship. The inter-species differences lie chiefly in the abundance, length or distribution of glandular or non-glandular trichomes, and the abundance or type of calcium oxalate crystals. It is also found that the appearance and disappearance of the calcium oxalate crystals in the anther of Inula japonica Thunb. seem to be related to the development of anther and pollen grains.