Controlling Bacteria

The Staphylococcus aureus bacterium, mentioned earlier, also causes mastitis (inflammation of the mammary glands) in cows. Neem's apparent ability to control certain strains of this bacterium may thus be of great economic importance to dairying in the nations where neem grows.

Also, the salmonella bacterium, in addition to affecting people, causes abortion in horses, cattle, and sheep, as well as a variety of infections in poultry and livestock.

Controlling Intestinal Worms

Trials in Germany showed that neem also works against intestinal nematodes in animals.17


Medicines from plants should, of course, be treated with the same caution as medicines from laboratories. Neem oil seems to be of particular concern. Consuming it, although widely practiced in parts of Asia, is not recommended. Doses as small as 5 ml have killed infants,18 and animal studies showed acute toxicity at doses as low as 14-24 ml per kg of body weight.19 It seems possible that this was caused by contaminants rather than by the oil itself. In Germany, toxicological tests using oil obtained from clean neem kernels resulted in no toxicity, even at a concentration of 5,000 mg per kg of body weight in rats. Nonetheless, caution is called for.

The leaves or leaf extracts also should not be consumed by people or fed to animals over a long period. There are anecdotal reports of renal failure in Ghanaians who were drinking leaf teas as a malaria treatment.

None of this should be confused with earlier statements. The compounds and seed-kernel extracts responsible for the insecticidal activity appear to be essentially nontoxic to mammals (see Appendix A).20


Information from H. Schmutterer. To be effective, the preparations had to have relatively high concentrations of azadirachtin.


Sinniah and Baskaran. 1981.


Gandhi et al., 1988.


Koul et al., 1990.

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