In a sense, most medicinal plants are poisonous, and the knowledge of medicinal and poisonous plants grew concurrently. In Ayurveda poisonous plants are indicated for use in a veaiety of ailments.

        Shivatatva ratnakara is an encyclopaedic work on toxicology, written in Samskrit, in the 17th century. In the 16th part of this work, medical toxicology was discussed. Khagendra mani darpana of the 14th century, written in Kannada, is almost exclusively on medical toxicology. These two works contain much more information than the Samhithas. Probably basing on these different works, a number of rural people have gained expertise in toxicology, in different parts of India, occasionally adding personal experience.

        The folk practice called kaimaddu, prevalent in Karnataka, is an occult use of toxicology. It is repulsive to detail the contents of this concoction, which reflects the venom of the human mind. Kaimaddu is a weapon seeped in superstition on the part of both the offender and the victim, and was employed to settle personal enemty. It is not always clear as to how a victim is made to consume the concoction. It is often given to the unsuspecting victim, disguised in food, probably by a trusted person. Once taken in, the victim is expected to suffer physically and mentally resulting in a wastage of the body leading to death. Surprisingly, even today, even in highly urban places including Bangalore, there are toxicologists who have a very busy practice in treating cases of kaimaddu, by administering a strong emetic, which is either Tylophora indica or Olea dioica, to expel the kaimaddu from the stomach, after which the victim regains his/her past glory. This is probably a reflection of the therapeutic benefits of emesis. But the saddening reflection of this issue is that, literacy and civilisation do not remove superstition, particularly when in desperation.

        The deep scientific interest in poisonous plants in India is indicated by th series of volumes published by CSIR.

        Current day interest in poisonous plants is to discover cytotoxic, mitostatic and other effects for use in drug development in cancer.

        Traditional Indian toxicology has been discussed in a considerable detail (Raut, 1993; Sathyanarayana Bhat and Kameswara Rao, 1993b). There are three aspects of traditional toxicology: a) treatment of bites and stings by poisonous insects like bees and scorpions, and snakes, using plants, b) treatment of disease by using poisonous plants, c) using plants as antidotes against poisoning by metals, plants and animals.

        A list of 158 species used in traditional toxicology is given in Appendix 20. This information was gathered from the toxicological texts, as well as by interviewing 16 ‘practitioners of toxicology’ (visha vaidya) in different parts of Karnataka. Those interviewed are listed in the section on the sources of information.

PLANTS USED IN VENOMOUS SNAKE BITES

        In the works of Charaka and Sushrutha, plant based treatment of bites and stings by snakes, insects, etc., was recorded.

        About 55, out of around 260 species of snakes in India, are poisonous. The poisonous snakes are mostly confined to rural places and forests. Both the people and the snakes in these areas normally avoid each other. Venomous snake bites are in actuality very few and accidental.

        Snake venom is synthesised and stored in glands, and is injected through the fangs to kill the snake’s natural prey. When a snake bites a human, the dose of the venom in relation to the body size is too small to produce the dramatic effect of immediate death (Sanmuganathan, 1998), but children may be more seriously affected than adults.

        Snake venom is not a single toxin. It is a complex mixture of enzymes (particularly phospholipase A2), toxic proteins, non-toxic proteins, carbohydrates, metals, lipids, free amino acids, neucleotides, bionic amines (Chang, 1979), a lectin and saponins. Each one of these components produces its own effects in the victim, the total picture varying from a serious respiratory failure to a mild ptosis. The syndrome of snake envenomation is described as ‘myasthenic’ (muscular weakness), rooted in neurotoxicity. Venom components are snake species specific. For example, krait venom does not have the components that cause haemostatic, renal and vasoactive dysfunction, which the venoms of the other poisonous snakes have. In addition, there are geographical variants of the same species of the snake. While a considerable amount of research was carried on the venoms of the cobra and the Russel’s viper, by and large studies to identify the specific biological effects of each one of the components of snake venoms have not been conducted. All effects of snake envenomation are reversible through an administration of antivenom and even by an appropriate clinical management, as shown by a study of 65 victims who reported at the hospital from 25 min to 92 h, after the snake bite (Sanmuganathan, 1998); and all saved.

        In the instance of a bite by a poisonous snake, the damage to the victim is more from shock than from the toxicity of the venom itself. First aid measures would certainly reduce the severity of toxic effects and the chances of death very considerably. People at risk from snake bites should be educated on the identification of the poisonous snakes, and the first aid to be administered. They should also be imressed upon the need to go to a hospital the soonest, with the offending snake, if killed. Often very precious time is wasted in quacks handling the case.