(a) The parts used: Almost all portions of the neem plant are useful in medicine: root, bark of the main trunk and the branches, leaf, flower, the wood, the gum, the exuding liquor or mad, or the neem toddy, the unripe and the ripe fruit, the mature seed and the oil extracted from it, and so on. As far as the bark is concerned it is its inner layer rather than the outer and particularly the fresh rather than the old and the stored bark that is preferred as the source of the medicine. The bark is an officially accepted drug in Indian Pharmacopea or the official stock list of Medicines and is called Azerachtl Cortex.
It is only the inner region of the bark that is specified as the acceptable source drug officially. This bark is usually employed in the form of an alcohol extract. Still however, it is the bark of the root that Is believed to be quicker and stronger in action by ayurvedic physicians rather than the bark from the main trunk or the branches or even the unripe fruit.
For medicinal purposes, fruits are collected when they are still small and before they reach half their mature size. They can then be cut into small pieces, dried in sun and stored. For extracting oil from the seed, it is better to collect the fruits before they fall down by themselves. This is because refining the oil is most advantageously done when the fruits are not soiled; the cleaner and the more fresh the seed, the better is the oil.
Neem wood forms a fairly well praised timber. It resembles the most famous mahogani wood (belonging to its own family Meliaceae) from which however it differs as follows: Its grains are not so sticky or adhesive and the wood itself is not so easily workable by the carpenter. It is however much used as a cheap timber but best praised as hofy and therefore most appropriate for shaping the statues of the gods and the goddesses. Because of its bitterness, it is resistant to termites.
(b) The Medicinal Reputation: The medical lore associated with neem is highly attractive and extremely varied. The plant is believed to be effective all round and so invaluable that there is a popular presumption among the Ayurvedists that half of their medicinal stock is this neem while all the rest of their drugs together constitute the other half. We give below a somewhat classified information of this lore gathered from several sources.
(C) General actions within the body: Ayurvedists consider neem as light in digestion but hot in effect, and cold in property but hot in effect and bitter in taste. It is pungent as well and is conducive to lower the digestive capacity. It cleanses the wound and helps in the ripening of all morbid swellings and hastening their cure. It is wholesome to children and an efficient destroyer of worm infection.
It heals up the wound, counteracts morbid swellings in general, pitta dosha, vata dosha and also poison. It is useful in leprosy and in quietening the sensation or burning or feverish heat at the chest. It relieves fatigue, thirst and tastelessness and is a good medicine in cough, fever and dysfunctions in blood as well as prameha or urinary disease.
It is rochaka or appetitive, grahi or constipative (but the fruits are bhedaka or purgative) and digestive of ama (or the incompletely digested food). It relieves the doshas of kapha and pitta, is stimulative to liver, a purifier of blood, a worm killer, ahrdya or unpleasant and a destroyer of the morbid swellings due to the vitiations of blood.
It is particularly useful in children where it is bitter but nourishing and also invigorative or strength giving and a destroyer of fever. In fevers associated with constipation, neem is used along with other drugs like chirayata (Swertia) and black pepper so as to counteract its own otherwise constipative action. It is particularly useful in periodic fever and the sores of upadamsha or venereal diseases, specially syphilis.
Against highly vitiated ulcers which do not heal up quickly and in the wounds and ulcers of a diabetic patient, neem is advised with good effect. It cleans them up as well as heals and acts as an efficient disinfective, also. Against kushta and small-pox it is a precious gift of nature. The three diseases for which neem is extensively recommended in their various stages are: leprosy, small pox and several skin diseases.