The plants collected and reported from different tribal and rural areas of Rajasthan. Species namely Azadirachta indica, Tinospora cordifolia, Phyllanthes emblica are used in diabeties. Boerhaavia diffusa, is generally used in liver disorders. Euphorbia hirta is often used for longer period against asthmatic problems for permanent recovery. Phyllanthus emblica are given to cure jaundice generally with buttermilk. The use of the plant parts as a crude drugs by various communities local people and vaidya’s in Rajasthan for various ailments no doubt indicates that the plant must have medicinal properties in it. Therefore, the plant requires a thorough screening of it's bioactive properties for the reported efficacies. Plant species namely Ageratum conyzoides, Calotropis procera, Piper nigrum are generally used as antileukaemic. Calotropis procera and Curcuma longa are used for face shadow, darkness and pimples on face. The collection, identification and documentation of ethnomedicinal data on biological resources are inevitable steps for bioprospecting. The native inhabitants are well-versed with the utilization of plants of their surrounding by their long trial and error method of using the herbal plants. These plants may serve as source of some important medicine against some major diseases. Therefore, these tribal and rural claims should be further validated scientifically. In the present work physical constant values have been estimated. Lower percentage of acid insoluble ash was recorded in Calotropis procera. High percentage of acid insoluble ash may indicate the probability of high content of certain inorganic minerals. According to annual reports of 1970-71 and 1974-75 of the pharmacognosy research unit, Drug research laboratory, Pune, ash value of powdered leaf of Calotropis procera was 19.85%. The differences observed in the ash values was probably due to the age at which the material was collected and also due to the locality. Carbohydrate metabolism is affected by drought through direct and indirect effects on photosynthesis and through several intermediate components and processes (Slayter, 1969). Under drought, there is a conversion of starch to sugars. This conversion is frequently associated together, although there are reports of reduced polysaccharide levels not being associated by an increase in sugar content. Reduced starch levels in cotton plants have been shown to be due to reduced photosynthesis and increased hydrolysis, as well as decreased carbohydrate synthesis (Eaton and Ergle, 1948). In the present work both the conditions that is either reduced starch level and increased sugar level or less amount of sugar and high amount of starch has been observed in various species. The cardiac-glycosides are particularly important source of unusual aligosaccharides derivatives (Reichstein and Weiss, 1962). The cardenolides are the more common and particularly abundent in the Calotropis procera. Sharples and Burkhard (1954) reported that fluctuation in carbohydrate content in influenced by seasonal environmental factors and by the growth activity of plants. 10-30% of the protein in a forage is converted into human food by ruminants whereas 40-60% of the protein can be extracted. Protein can be extracted more readily from soft bushy leaves than from those that are fibrous and dry. Leaves that give glutious or slimy extracts are difficult to handle (Prie, 1968). Good yield of protein have come from leaves that are by products, e.g., beans, jute, peas, potato and sugar beet. In young leaves of plants growing under good conditions, as much as 40% of the dry matter may be protein and 30% is fairly common. As the leaf matures the protein content falls. This may be caused by a change in the ratio of fibrous tissue to tissue rich in plastids but it is often caused by nutritional deficiencies. The seeds of Cucurbitaceae are outstandingly high in protein contents (28%), seeds of most of the members of family Euphorbiaceae are relatively high in protein and oil contents (Smith, 1954). The high quality proteins is also indicated for certain families like Chenopodiaceae, Polygonaceae and Amaranthaceae. In the present work it has been found that Asclepiadaceous plant i.e. Calotropis procera have rather low protein content, ranging from 3.05 to 11 percent. In recent years, efforts have been made to develop new methods of proteins production. One of these methods has been the extraction of proteins from plant leaves for consumption by human being and non ruminant animals (Chayen et al., 1961; Morrison and Pirie, 1961). Recent feeding trials suggested that leaf proteins concentrate may be equal to or better in nutritive value than proteins, such as meat, white fish meat and milk of certain species of non-ruminant animals (Winter and Funk, 1956). Plant protein may turn out to be of great medicinal importance and foodstuffs. However, there is a great paucity of information on the sources and uses of plant protein (Pirie, 1971, 1978). Thus, in conclusion we can say that phytochemical screening of medicinal plants would be much help in locating the source of pharmacologically active chemical compounds like alkaloids, tannin, sterols, phenolic constituents etc. Further phytochemical information is at times decisive in solving taxonomic problems. (Gibbs, 1974; Swain, 1963). It is hoped that screening data will be useful for the development of small scale industries engaged in extraction of crude drugs. Flavonoids form a major class of phytochemicals and are universally distributed among vascular plants. Flavonoids have been reported from a number of plants belonging to Compositae. Rienacker in his article “The future of medicines” says a new type of medicinal scientist are appearing on the scene who no longer regard diseases mechanically as local phenomena but as symptoms resulting from a general state of disorganizations and disharmony (Weiss and Fintelmann, 2000). Ayurvedic system of medicines a large number of plants are employed in the traditional system of medicines for the treatment of several diseases like cancer (Jain, 1991; Sharma and Kumar, 2003), depression and other nervous disorders (Mishra and Kumar, 2000), diabetes (Raghunandan & Mitra, 1982; Gupta & Kumar, 2002), rheumatism (Sanghi and Kumar, 2001), Leprosy (Sanghi and Kumar, 2003), skin disease (Shivani and Kumar, 2002) Urinary stone track disease (Mishra and Kumar, 2001) hepatic disease (Sharma and Kumar, 2003), disease of digestive system (Choudhary and Kumar, 2001), Malaria(Yadav and Kumar, 2002) paralysis (Sharma and Kumar, 2001). Medicinal plants with anti-tumour potential are listed below: Antitumour triterpenoids derived from Celastrus hindsii. (Kuo Y.H., 1997) Ageratum conyzoides Aloe vera Curcuma longa Vinca rosea Taxus baccata Medicinal plants with anti-HIV potential Acquired immunodeficiency syndrome (AIDS) has been a serious life-threatening health problem since 1981 and is the most quickly spreading disease of the century. On account of recent reports of WHO and UNAIDS, at the end of 2001, an estimated 40 million people globally were living with HIV, out of them about 22 million people had died. Plants with anti-HIV potential are listed below: (1) Acer okomotoanum (Family: Aceraceae) (2) Artemisia annua (Family: Asteraceae) (3) Croton tiglium (Family : Euphorbiaceae) (4) Curcuma longa (Family : Zingiberaceae) (5) Glycyrrhiza lepidota (6) Polyalthia suberosa (7) Phyllanthus myrtifolius. Out of an estimated 250,000 higher plants, less than 1% has been screened pharmacologically and very few in regards to AIDS. Therefore, it is prudent to look for options in herbal medicine for AIDS as well. It should be noted that many of the anti-HIV drugs currently used in chemotherapy either are derived directly from natural products or are synthetic based on natural product models. Natural product derived active compounds serve as important lead molecules as demonstrated in the case of the development of calanolides. The rapid evolution of new anti-HIV clades and drug resistant variants in AIDS patients, as well as resurgence of other infectious diseases, such as drug resistant tuberculosis and hepatitis requires the development of innovation but reproducible technology targeting the critical elements for drug discovery and development. The goals of medicine no matter to which group it belongs i.e. the welfare of the patient. One can look towards a future of integrated medicine and hope that research in alternative medicine will help to identify what is safe and effective rather than marginalizing, unorthodox medical claims and findings.