The intimate relationship between the human and plant world has evolved over generations of experience an practices. The tribal people and ethnic races throughout the world have developed their own culture, customs, cults, religious rites, taboos, totems, legends and myths, folk-fores and song, foods, medicinal practices, etc. The term "Ethnobotany” denotes the total relationship between man and vegetation. It is also considered as 'branch of economic botany, which deals with the role of plants in life and culture of aborigines and tribal people. The accumulated traditional knowledge of the early past has been preserved in to writings and practice of herbalists.The therapeutic efficacy of herbal medicines led to the evolution of Ayurveda (2500-600B.C) which literally means ‘science of life’. In the name of development, as people moved away from Mother Nature, they became more prone to diseases, decay and degeneration. Most of the present day diseases are life style diseases However there is again a revival of drugs being obtained from vegetable sources than at any time in history. Medicinal plants are now in a “come back” phase with the last two decades seeing people shifting their focus back to the forgotten traditional natural green remedies. There are 248 botanical drugs enlisted from Rigveda, which are mentioned mainly in Atharva veda and Rigvedas. The Samhita and Nighantus can also be used as valuable ethanobotanical resources. He also reviewed the Nighantus and other treatises and listed the plants mentioned there in. Medicinal plants are distributed across diverse habitats and landscape. Around 70 per cent of India’s medicinal plants are found in tropical areas. Some ethnobotanical work in India was done in botanical survey of India. The state of Rajasthan is situated between 23º3’ and 30º12’ N latitude and 69º30’ and 78º17’ E longitude . A major portion of western Rajasthan has desert soils and sandy plains. The average annual rainfall in the state is 525-675 mm, and the annual precipitation in different tracts of Rajasthan varies from 13 mm to 1766 mm. Rajasthan is rich in biodiversity which has a great economic value. This forest includes roughly 7 % of depleted and denuded forests. Biodiversity of Rajasthan is related with the Aravalli hills. Anogeissus pendula Edgew. forests cover more than half of the total forest area in the state. Recently, several studies have been conducted on Ayurvedic crude drugs for cure of digestive diseases, leprosy and skin diseases, malaria and paralysis, herbal cosmetics. Medicinal plants are distributed across diverse habitats and landscape. Around 70 per cent of India’s medicinal plants are found in tropical areas. Although less than 30 per cent of the medicinal plants are found in the temperate and alpine areas and higher altitudes they include species of high medicinal value. One third is tree and an equal portion includes shrubs, and the remaining one third are herbs, grasses and climbers. The major families which include medicinal plants are Liliaceae, Fabaceae, Euphorbiaceae, Rutaceae, Solanaceae, Asteraceae, Cucurbitaceae, Rubiaceae, Poaceae, Malvaceae etc. The plants used in ayurvedic drugs were mostly collected from the field conditions and this has resulted in considerable loss of biodiversity and endangering several plant species. Conservation of these valuable plant species has become imperative due to interest in herbal medicines for healthcare all across the world. Around 80% population of India live in rural areas; utilize traditional medicinal system, which are based on largely Ayurvedic medicine. Studies were conducted in different regions of Rajasthan and other tribal areas. Data was also collected from the different areas out of Rajasthan specially rural and tribal areas where of herbal drugs is most common and other ethnobotanical practices are under going. The people of Rajasthan can be broadly divided into ; those living into extreme wheather condition as in Western Rajasthan and others in milder climate. Rajasthan has rich biodiversity consisting of a large number of plants, some of which are used for their medicinal value. A large number of medicinally important tree species are present on Aravalli hill range and other areas including less hospitable North–West Rajasthan. An attempt was made to characterize tree species of the region and detailed pharmacognostical studies on some selected plants were conducted. Ethnobotany is usually defined as anthropological approach to botany. Several methods of ethnobotanical research relevant to medicinal plants like archaeological search in literature, herbaria and the field studies were used in the present investigations. The relationship between people of primitive societies and their plant environment was studied. Though ethnobotany provides several approaches in plant researches, here only the resources which help in mainly in medicinal research were considered Flowers are profusely mentioned in folk and religious songs. Certain trees like Basil (Ocimum sanctum Linn.), Palas (Butea monosperma O.Kuntze.), Sandal wood (Santalum album Linn.) find a prominent place in songs sung in religious rites. Sandal (Santalum album Linn.), turmeric (Curcuma domestica Valeton.) and other plants are used in the formation of a paste for improving the complexion of a bride. Brides use sandal (Santalum album Linn.), rose (Rosa damascena Mill.) to perfume their body. Acacia concinna DC. Vern. (Shikakai) pods are blended into shampoo and hair cleanser with Sapindus mukorossi Gaertn Vern. Ritha to promote hair growth and to stop hair splitting, falling and dandruff. Khejiri ( Prosopis cineraria Linn.) is most common tree in the Thar desert of Rajasthan. Recent researches indicate that it brings up moisture and nutrients from underground soil for crop grown above. Charcol of Acacia catechu Willd. (Katha)is used in iron smelting. The stem of Abrus precatorius Linn.(Chrimiti)is used by jewellers to increase adhesion while soldring delicate ornament. Cooling screens in hot weather are prepared from Alhagi pseudo-alhagi Linn.(Javasa) The following tree species also found in the sandy areas – Prosopis cineraria, Balanites aegyptiaca, Zizyphus mauritiana, Tecomella undulata, Ailanthus excelsa, Acacia nilotica var. indica and Holoptelea integrifolia. Some of the species which occur exclusively in the rainy season e.g. Cleome gynandra, Sesbania sesban, Tribulus terrestris, Sesamum indicum, Mollugo cerviana, Trianthema Portulacastrum, Aristida spp. Eleusine spp. and Cynodon dactylon. A large majority to the trees in the area are restricted to the hills. Sterculia urens, Commiphora wightii, Anogeissus pendula, Boswellia serrata, Lannea coromandelica, Rhus mysorensis, Adina cordifolia, Diospyros melanoxylon, Wrightia tinctoria, Cassia fistula,. Aegle marmelos. Cordia gharaf and Ficus racemosa occur naturally on the hills but have probably been introduced in other areas. Some other species like Grewia tenax, Butea monosperma and Acacia senegal are restricted to the bases of the hills. About 500 tribal communities are representing 7.76 per cent of the total population of the country. It is spread over 19 per cent of the total area of the nation. The total tribal population of Rajasthan state is 5,474,881 which is 12.44 per cent of the total population of this state. The tribals of Rajasthan constitute 8.07% of the total population of tribals in India. Several tribes inhabited in the state of Rajasthan, namely – ‘Bhil’, ‘Bhil-Meena’, ‘Garasia’ ‘Damor’, ‘Dhanaka’,, ‘Kathodia’, ‘Meena’, ‘Patelia’ and ‘Saharia’. Besides these, there are some nomadic, semi-nomadic tribes and denotified communities also. Nomadic tribes are ‘Banjara’, ‘Gadia–Lohar’ and ‘Kalbelia’, whereas semi-nomadic tribes are ‘Rebari’, ‘Jogi’ and ‘Masani’. ‘Bori’, ‘Kanjer’, ‘Sansi’, ‘Bhat’ are included in denotified communities. Morphological studies were conducted on some important medicinal plants. They included Aloe ferox, Tinospora cordifolia, Aloe vera, Tinospora crispa, Ocimum sanctum, Ocimum basilicum, Pergularia daemia. Anatomical studies were conducted on Tinospora cordifolia, Aloe vera, and Calotropis Procera (Ait.) R.Br.. Pharmacognosy includes the study of the proper horticulture, harvesting and uses of the raw medicinals found in nature. Its scope includes the identification or authentication of crude drugs (using macroscopical, microscopical, radiological or chemical methods), and their bio-pharmacological and clinical evaluations. Pharmacognostical studies were conducted on some selected plants which included Aloe vera, Acacia nilotica Linn, Cassia senna, Tinospora cordifolia (Willid.) Miers, Ricinus communis, Ocimum sanctum Linn. Chlorophytum tuberosum (Roxb). The plants of the family Euphorbiaceae are used in folk medicines to cure skin diseases, gonorrhea, migraines, intestinal parasites, and warts. The polycyclic diterpenoids with tigliane (phorbol esters), ingenane (ingenol esters), jatrophane, and lathyrane skeletons are among the most studied diterpenoids isolated from Euphorbia plants. These diterpenoids are biologically active in diverse ways; they have been found to be skin-irritants, tumor-promoters, anti-cancer agents, and recently, agents for overcoming multidrug-resistance (anti-MDR) Several of the related myrsinane diterpenoids have been isolated from Euphorbia species in China, Turkey, and Iran. Thus the present investigations have revealed the importance of ethnobotanical and pharmacognostical studies for developing suitable medicines for the masses which will not have side effects of allopathic medicine.