Yarnell E, Abascal K. Nigella sativa: holy herb of the Middle East. Altern Complement Ther. April 2011;17(2):99-105.

Nigella (black cumin; Nigella sativa) has been used traditionally in the Middle East, Eastern Africa, and Asia, but not so much in Western Europe and the Americas. Clinical trials have supported its use for treating allergies. It has also been studied for its use in withdrawal and abstaining from opioids and in improvement of lipid profiles and/or to decrease seizure frequency. These authors examine the herb's chemistry, its various uses, and its safety and dosing.

Nigella contains terpenoids (particularly thymoquinone but also thymol and thymohydroquinone) and fatty acids. Isolation of terpenoids by steam distillation or supercritical carbon dioxide results in a volatile oil. A mixture of the fatty acids, when pressed out, constitutes a fixed oil. Published research often does not clarify whether a volatile or fixed oil of nigella was used.

Nigella may help patients avoid acute asthma attacks or reduce the severity of acute attacks if they occur. Cited are several Iranian clinical trials that support this claim. Other cited studies support the use of nigella in relieving the symptoms of allergic rhinitis. Based on these studies, authors conclude that nigella "appears to be potentially helpful and safe for people with atopic disease, both for acute symptoms and to prevent them from occurring."

Animal studies have investigated the effects of nigella and thymoquinone on the nervous system. In human studies, a double-blind clinical trial of 22 Iranian children with epilepsy reported that seizure frequency was significantly reduced when the children were taking thymoquinone compared with placebo. In an open trial in Pakistan that included 50 male opioid abusers, those taking nigella powder (some taking more than others) experienced significantly reduced acute withdrawal symptoms compared with placebo. The higher dose was more effective than the lower dose.

Animal studies have shown that nigella exhibits antidiabetic effects and is as effective as metformin for improving glucose tolerance. In a clinical trial in Pakistan, men and women with dyslipidemia but not diabetes mellitus received either nigella powder or placebo twice daily for six weeks. The change in total cholesterol level barely missed statistical significance. Other lipid measures, as well as fasting blood glucose, waist circumference, and blood pressure were not significantly different, though the trend was in favor of nigella.

In vitro and animal studies suggest that nigella and thymoquinone may have antineoplastic activity and may influence the immune system to help fight cancer. Results need to be verified in human studies.

The use of nigella as food attests to its high degree of safety. Nigella has also been found safe in numerous preclinical studies. The authors note, however, that isolated thymoquinone can be overdosed and should either be used in lower doses or avoided until more human clinical trials are completed.

Regarding dosage, for most applications, the authors recommend 500 to 1000 mg of crude nigella powder three times daily; doses for fixed oil are similar. The dose of tincture should be 3-5 mL three times daily, made with at least 60% ethanol.

The authors conclude that nigella is a well-researched herb with a strong tradition for use in patients with allergies and asthma. It may also be effective in patients with seizure disorders, opioid addiction, dyslipidemia, and other conditions. The authors suggest that "further research is needed, but [that] this resource should be more widely used in the West."