Parts used 
Flowers, leaves, bark, seeds and oil, root bark, young fruit, gum.

Pharmacological action
Root bark and fruit are astringent, tonic and anti periodic.
Bark is bitter, tonic, astringent, anti periodic and vermifuge
Fruit is emollient, purgative and antihelmentic
Oil is local stimulant, insecticide and antiseptic.
Leaves are antihelmentic
Flowers are stimulant, tonic and stomachic
Gum is stimulant and demulcent
Neem also possess anti spirochaetal and emmanogogue properties

Actions and uses in ayurveda
Jvara, aamsotha, vrana, kustha, prameha, netraroga, krimiroga, visaroga, aruci, vranam, chardi.

Indications
Photochemical: The bark exudes a clean bright amber colored gum which is collected in small trees or fragments. It contains a bitter alkaloid named margosine in long white needles. Leaves contain a small bitter substance of same chemical character but much more soluble in water. Seeds contain 10-30% of a yellow bitter fixed oil which is extracted by boiling. The oil is deep yellow in color and contains free and volatile fatty acids. The volatile fatty acids contain stearic and oleic acid with a small amount of lauric acid.

The sap contains glucose, sucrose, gums and coloring matter, proteids and ashes, containing potassium, iron, aluminium, caslcium and carbon dioxide.

Properties and action
Rasa: tikta, kashaya
Guna: laghu
Virya: sita
Vipaka: katu
Karma: vatala, pittanashak, grahi
Preparations: powder and decoction

• Blood and haemopoeitic tissue: it is a blood purifier and hence is used in all skin troubles. It has a marked action on liver

• Central nervous system: it is a nervine stimulator and is used in tetanus

• Digestive system: it is used in loss of appetite, constipation and belching. It is used as a wormicidal in intestinal worms

• Reproductive system

• Skin: it is used against malaria, intermittent fever and other paroxysmal fevers, convalescence after fever. It is also use din leprosy, psoriasis, eczema etc.

• Genito- urinary system: it is used in leucorrhea, primary secondary and tertiary syphilis.

Women: Vaginal cream and suppositories made with neem oil from seeds are quickly becoming the birth control method. When tested against human sperm neem extract was able to kill human sperm in 5 minutes. Neem has aproven ability to prevent pregnancy. It prevents implantation and even has abortificant nature.

Men: Neem has become the first truly effective birth control pill for men. Neem oil capsules if taken for one month produce reversible male infertility without affecting sperm production or libido.

Dose: Powder 1-3 gms

1. Prof P.V Sharma, Dravya Guna Vigyana, Vol II, pg 149-151
2. Dr.KM Nadkarni, The Indian Materia Medica, Vol.I, pg 776-784
3. The Ayurvedic Pharmacopoeia Of India, Part I, Vol.II, pg 124-125