Plants have been used in traditional medicine for several thousand years 1. The knowledge of medicinal plants has been accumulated in the course of many centuries based on different medicinal systems such as Ayurveda, Unani and Siddha. In India, it is reported that traditional healers use 2500 plant species and 100 species of plants serve as regular sources of medicine 2. During the last few decades there has been an increasing interest in the study of medicinal plants and their traditional use in different parts of the world 34567. Documenting the indigenous knowledge through ethnobotanical studies is important for the conservation and utilization of biological resources.

Today according to the World Health Organization (WHO), as many as 80% of the world's people depend on traditional medicine for their primary healthcare needs. There are considerable economic benefits in the development of indigenous medicines and in the use of medicinal plants for the treatment of various diseases 8. Due to less communication means, poverty, ignorance and unavailability of modern health facilities, most people especially rural people are still forced to practice traditional medicines for their common day ailments. Most of these people form the poorest link in the trade of medicinal plants 9. A vast knowledge of how to use the plants against different illnesses may be expected to have accumulated in areas where the use of plants is still of great importance 10.

In the developed countries, 25 per cent of the medical drugs are based on plants and their derivatives 11. A group of World Health Organization (WHO) experts, who met in Congo Brazzaville in 1976, sought to define traditional African medicine as 'the sum total of practices, measures, ingredients and procedures of all kinds whether material or not, which from time immemorial has enabled the African to guard against diseases, to alleviate his/her suffering and to cure him/herself' 12. Traditional medical knowledge of medicinal plants and their use by indigenous cultures are not only useful for conservation of cultural traditions and biodiversity but also for community healthcare and drug development in the present and future 2.

Ethnobotany is not new to India because of its rich ethnic diversity. Jain 13 printed out that there are over 400 different tribal and other ethnic groups in India. The tribals constitute about 7.5 percent of India's population. During the last few decades there has been an increasing interest in the study of medicinal plants and their traditional use in different parts of India and there are many reports on the use of plants in traditional healing by either tribal people or indigenous communities of India 1415161718192021. Apart from the tribal groups, many other forest dwellers and rural people also posses' unique knowledge about plants 13.

The objective of this study was to interact with local traditional healers and document their knowledge on medicinal plants, their usage and the types of diseases treated etc. Kancheepuram is one of the 30 districts in Tamil Nadu and the traditional healing systems are still popular here. The present-day traditional healers are very old. Due to lack of interest among the younger generation as well as their tendency to migrate to cities for lucrative jobs, wealth of knowledge in this the area is declining. So far no systematic ethnobotanical survey has been made in this area and this is the first report on the medicinal plants used by the local traditional healers. A perusal of the literature reveals that, some of the ethnomedicinal works has been done in the forests of nearest districts in Tamil Nadu in the last two decades 22232425. During the course of exploration of ethnomedicinal plants of the district, the informations have been gathered from the healers of rural villages found near forest areas where the people depend mostly on forests for their need and have sound knowledge of herbal remedies.

The results of the survey are presented in Table 1 and the families of the plants are arranged in alphabetical order. The present investigation comprises 85 species of ethnomedicinal plants distributed in 76 genera belonging to 41 families. For each species botanical name, family, local name, parts used, methods of preparation, administration and ailments treated are provided. Traditional healers are using these plants to cure diseases related to skin problems, cold, fever, cough, headache, diarrhoea, fertility problems, toothache, stomach ache, wounds, diabetes, rheumatism, asthma, dysentery, small pox, bone fractures, earache, hair loss and poison (snake, scorpion and insect) bites (Figure 4).

Herbs (39 species) were found to be the most used plants (Figure 2) followed by trees (21 species), shrubs (14 species) and climbers (11 species) in descending order. The most dominant families in the study were Euphorbiaceae (7 species), Verbenaceae (5 species), Caesalpiniaceae, Solanaceae and Apocynaceae (4 species), Acanthaceae, Asclepiadaceae, Asteraceae, Fabaceae, Lamiaceae, Malvaceae, Moraceae, Rubiaceae and Rutaceae (3 species). Other families with low number are listed below: Amaranthaceae, Anacardiaceae, Boraginaceae, Capparaceae, Liliaceae and Cucurbitaceae (2 species), Aizoaceae, Annonaceae, Araceae, Combretaceae, Convolvulaceae, Cyperaceae, Lauraceae, Lythraceae, Meliaceae, Menispermaceae, Sapindaceae, Rhamnaceae, Poaceae, Nyctaginaceae, Myrtaceae, Moringaceae, Mimosaceae, Sterculiaceae, Violaceae, Vitaceae and Zygophyllaceae (1 species).

Local traditional healers are commonly using the following plants to treat more number of diseases. They are: Vitex negundo, Wedelia calendulacea, Ocimum gratissimum, Cynodon dactylon, Solanum nigrum, Azadirachta indica, Pongamia pinnata, Aristolochia indica, Solanum trilobatum, Adhatoda vasica, Phyllanthus emblica, Ocimum sanctum, Murraya koenigii, Ficus benghalensis and Cassia auriculata. Preference for their use may be related to their availability.

Different parts of medicinal plants were used as medicine by the local traditional healers. Among the different plant parts, the leaves were most frequently used for the treatment of diseases followed by whole plant parts, fruit, stem, root, stem and root bark, seed, flower and latex. The methods of preparation (Figure 3) fall into four categories, viz.: plant parts applied as a paste (38%), juice extracted from the fresh plant parts (24%), powder made from fresh or dried plant parts (20%), some fresh plant parts (6%), and decoction (12%). External applications (mostly for skin diseases, snake bites and wounds) and internal consumption of the preparations were involved in the treatment of diseases.

It was observed that, most of the remedies consisted of single plant part and more than one method of preparation. However, many of the remedies consisted of different parts of the same plant species to treat single or more diseases. For example, Andrographis paniculata – leaf paste is used to treat poison bites and leaf powder is used to treat diabetes; Gymnema sylvestre – root powder is used to treat poison bites and leaf powder is used to treat diabetes; Ricinus communis -juice extracted from leaves is used to increase secretion of milk and oil obtained from seeds is used to treat stomach ache; Azadirachta indica – leaf paste is used to treat small pox, rheumatism and skin diseases and young twigs are used as tooth brush; Ficus benghalensis – stem latex is used to treat heel cracks and young twigs are used as tooth brush; Moringa oleifera – boiled leaves are used to reduce body heat, to treat indigestion and eye diseases and flowers are used to cool the eyes and increase sperm production; Zizyphus mauritiana – decoction of leaf is used to get relief from body pain and bark powder is used to treat wounds; Solanum torvum – juice extracted from the leaf is used to reduce body heat and unripe fruits are used to strengthen the body.

Moreover a single plant is used for more than one disease. For example, Andrographis paniculata (diabetes and scorpion bites), Trianthema portulacastrum (constipation and asthma), Aerva lanata (cough, sore throat and wounds), Gymnema sylvestris (diabetes and poison bites), Wattakaka volubilis (rheumatic pain, cough, fever and severe cold), Sphaeranthus indicus (skin diseases and piles), Heliotropium indicum (wounds and skin affections), Cassia absus (wounds and skin affections), Cassia occidentalis (scabies and bone fractures), Terminalia arjuna (wounds, headache and tooth infections), Mukia maderaspatana (cold and cough), Cyperus rotundus (milk secretion and scorpion bites), Euphorbia hirta (wounds and lip cracks), Phyllanthus emblica (cold and cough), Ricinus communis (milk secretion ad stomachache), Clitoria ternatea (eye diseases and headache), Pongamia pinnata (wound and gas trouble), Coleus aromaticus (indigestion and cough),Leucas aspera (headache and fever), Ocimum sanctum (cough, cold and headache), Cinnamomum verum (cough, dysentery and body cooling), Aloe vera (hair loss and good sleep), Azadirachta indica (small pox, rheumatism and skin diseases), Moringa oleifera (body heat, indigestion, eye diseases and to increases sperm production), Syzygium cumini (swellings and body heat), Zizyphus mauritiana (body pain and wounds), Citrus aurantifolia (fever, headache and cold), Cardiospermum halicacabum (throat infection and headache), Solanum torvum (to reduce body heat and to strengthening the body), Solanum trilobatum (cough and itching) and vitex negundo (headache, fever, cold and cough) and these recipes are prepared using different ingredients of non-plant origin such as water, salt, honey, etc.

Common health problems in the sites of the study area were skin problems such as wounds, cuts, burns and skin diseases and the largest number of the remedies (wounds – 16 remedies and skin diseases – 9 remedies) was used to treat these troubles. Several studies have enumerated the plants used for wound healing and skin diseases in various parts of the world 14323334. 24 remedies were used to alleviate problems of the respiratory system such as cold, cough and asthma. Most of the plants in Lamiaceae were used to treat cold, cough, fever, headache and asthma. Ghorbani 35 reported 16 plant species that were used for respiratory diseases in north Iran and safety and efficacy of the treatments for respiratory track infections were reviewed 36. Common ailments such as headaches or coughs are considered to be diseases with natural causes and hence their symptoms are treated at the household level, without resource to magical practices 12. In the present study eight remedies (Terminalia arjuna, Leucas aspera, Ocimum sanctum, Sida acuta, Citrus aurantifolia, Cardiospermum halicacabum, Lantana camara and Vitex negundo) were used to get relief from headache. Recently Ignacimuthu et al 37 reported that Ceropegia candelabrum, Pergularia daemia and Vitex negundo were used by tribals for the treatment of headache.

Traditional healers of Kancheepuram district used nine plant species to treat stomach problems (three plants to treat stomachache and six plants to cure digestive problems). In North-Western Patagonia the people of Curruhuinca community were affected with digestive problems and the highest fidelity level was found for species utilized for treating digestive ailments 38 and Ghorbani 35 reported that there were 48 plants for the treatment of gastrointestinal disorders in north of Iran. The tribal people of Western Madhya Pradesh of India used 13 plants for the treatment of jaundice 19. In the present study only Phyllanthus amarus was used for the treatment of jaundice. Abutilon indicum, Azadirachta indica, Ficus benghalensis and Terminalia arjuna were used to treat dental problems. Various studies have reported on the indigenous use of medicinal plants in the treatment of oral diseases [39 &21]. Andrographis paniculata, Catharanthus roseus and Gymnema sylvestre were used to treat diabetes by the local traditional healers. Chherti et al 15 reported that the tribal people of Sikkim and Darjeeling Himalayan region in India utilized 37 species of plants belonging to 28 different families as antidiabetic agents.

The survey indicated that, the study area has plenty of medicinal plants to treat a wide spectrum of human ailments. Earlier studies on traditional medicinal plants also revealed that the economically backward local and tribal people of Tamil Nadu prefer folk medicine due to low cost and sometimes it is a part of their social life and culture 404142434445. It is evident from the interviews conducted in different villages, knowledge of medicinal plants is limited to traditional healers, herbalists and elderly persons who are living in rural areas. This study also points out that certain species of medicinal plants are being exploited by the local residents who are unaware of the importance of medicinal plants in the ecosystem.

This study concluded that even though the accessibility of Western medicine for simple and complicated diseases is available, many people in the studied parts of Kancheepuram district is still continue to depend on medicinal plants, at least for the treatment of some simple diseases such as, cold, cough, fever, headache, poison bites, skin diseases and tooth infections. Well-knowledged healers have good interactions with patients and this would improve the quality of healthcare delivery. The present-day traditional healers are very old. Due to lack of interest among the younger generation as well as their tendency to migrate to cities for lucrative jobs, there is a possibility of losing this wealth of knowledge in the near future. It thus becomes necessary to acquire and preserve this traditional system of medicine by proper documentation and identification of specimens.