The healing properties of neem are mainly due to some bitter substances, known as triterpenes (limonoids), with azadirachtin as one of the main active ingredients. In addition, neem contains beta-sitosterol, tannins, polysaccharides, flavonoids and essential oil.

An extract obtained from the leaves or bark has both antibacterial and antiviral effect, with little or no toxicity. The extract can be used internally as a treatment for asthma, sore throat, tuberculosis, eczema, jaundice, stomach ulcers, diabetes, arthritis, and rheumatism.

The herb can be used to eliminate unwanted intestinal parasites, and as an anti-fungal agent for candida. In addition, it is sometimes used to treat hepatitis A and B. Studies have shown that the neem oil has anti-inflammatory and bactericidal properties and that it, at least to some extent, can be used to reduce high fever and lower high blood sugar.