This information describes the common uses of Neem, how it works, and its possible side effects.

How It Works

Neem has anticancer effects. More studies are needed to test its effects in humans.

Neem is an herb that is used as food, in traditional medicine for skin conditions, and for stomach ailments. It is also used as a disinfectant against pests and parasites. Some lab studies show that neem extracts have anticancer activities by inhibiting cancer cell growth. However, there are no human studies showing it to be an effective cancer treatment.

Adverse reactions caused by neem oil have been reported in both children and adults.

Purported Uses

  • Ulcers
    A small study found neem bark extract effective in reducing stomach acid secretion without any adverse effects. More studies are needed in humans.
  • Cancer
    In vitro studies show neem can inhibit cancer cell growth. It has not been studied as a treatment for cancer.
  • Antiviral
    Neem extract has been shown to increase CD4+ cell count and bodyweight in a small number of HIV+ volunteers.
  • Oral hygiene
    Neem can reduce oral plaque and bacterial count. It is used as mouth rinse in traditional medicine.
  • Pesticide/fungicide
    Neem oil has been used externally against pests and lice.

Patient Warnings

Swallowing neem oil can cause severe adverse effects in children.

Side Effects

  • Vomiting, drowsiness, diarrhea, and seizures associated with coma have been reported.
  • Allergic contact dermatitis.
  • Acute contact dermatitis were observed on the scalp and face of a patient following use of neem oil for loss of hair.
  • Poisoning and neurotoxicity reported in a 35-year-old woman following consumption of a neem-based pesticide, requiring intensive medical care with mechanical ventilation.