Chemotherapy, radiotherapy... could black seed oil help patients cope with cancer treatments?

Chemotherapy and radiation therapy are pillars of cancer treatment. Although they have substantially contributed to improving patient survival, they can also cause significant side effects.

Chemotherapy is based on the administration of cytotoxic drugs designed to halt the proliferation of cancer cells. It is used alone or in combination with other techniques (surgery, radiotherapy, immunotherapy...), depending on the type of cancer and its stage of progression. Chemotherapy relies on targeting rapidly dividing cells, a hallmark of tumor cells. However, this mechanism is not exclusive to cancer cells: certain healthy cells, such as those in hair follicles, bone marrow, the digestive mucosa, or the nervous system, also renew themselves rapidly. This lack of specificity accounts for a large part of the observed side effects, including hair loss, nausea and vomiting, severe fatigue, digestive disorders, peripheral neuropathies, cardiovascular damage, and even transient cognitive impairments.

Radiation therapy, for its part, uses ionizing radiation to destroy tumor cells by inducing DNA damage that prevents them from dividing. However, once again, the effects of radiation are not limited to cancer cells: healthy tissues near the irradiated area can be affected. Adverse effects depend on the delivered dose, the organ involved, and the patient’s individual characteristics. They may appear early, as skin reactions, mucosal inflammation, or marked fatigue, or develop later as fibrosis or functional disorders. Technological advances have improved tumor targeting and reduced healthy tissue exposure, but radiation‐induced toxicity remains a central challenge in oncological care.

Some of the scientific literature suggests that Nigella sativa, and more specifically its primary active compound, thymoquinone, may exert a protective effect against certain adverse effects induced by anticancer treatments, particularly those related to oxidative stress.

These studies remain primarily experimental, but they offer valuable insights into the potential mechanisms involved. Several animal studies have shown that administration of oil or extracts of Nigella sativa can limit chemotherapy‐induced renal toxicity, particularly cisplatin, but also methotrexate, doxorubicin, or 5‐fluorouracil. These anticancer agents are known to generate a substantial production of reactive oxygen species, leading to oxidative damage in kidney cells.

In these experimental models, Nigella sativa (black seed) and thymoquinone reduce lipid peroxidation, enhance the activity of endogenous antioxidant enzymes such as superoxide dismutase and catalase, and improve biomarkers of renal function. From a histological perspective, a reduction in renal tissue lesions is also observed when black seed oil is administered both before and after exposure to chemotherapeutic agents.

Beyond the kidney, some studies suggest a broader hepatoprotective and antioxidant effect of the nigella. Seed extracts of Nigella sativa have notably shown an ability to mitigate the oxidative stress and liver damage induced by doxorubicin or exposure to gamma radiation. These findings suggest that thymoquinone’s antioxidant properties may, in certain experimental settings, help protect healthy tissues from treatment-related collateral damage without directly interfering with the treatments’ cytotoxic action on tumor cells.

For example, a study conducted on rats showed that a single dose of cisplatin (6 mg/kg) induced acute kidney injury via a massive production of free radicals. Oral administration of black seed oil (2 mL/kg), both before and after chemotherapy, made it possible to limit the rise in biomarkers of renal insufficiency, namely serum creatinine and blood urea. At the cellular level, black seed oil preserved the activity of enzymes responsible for proper tubular function in the kidneys, as well as those involved in carbohydrate metabolism. These biochemical results are supported by histological analysis, which reveals severe renal lesions in animals treated solely with cisplatin, compared to markedly attenuated damage in the group co-treated with black seed oil.

The overall data suggest a protective role of Nigella in attenuating chemotherapy-induced oxidative stress and renal tissue damage in a preclinical setting.

Another experimental study examined the ability of a Nigella sativa seed extract to attenuate the combined toxicity of doxorubicin and radiotherapy. In this protocol, rats received either doxorubicin, gamma irradiation, or both over several weeks, inducing marked oxidative stress and impaired liver function. These treatments led to a significant decrease in endogenous antioxidant defenses, accompanied by increases in lipid peroxidation markers and disruptions in hepatic enzyme activity. Daily oral administration of a Nigella sativa seed extract (2 g/kg), initiated before and continued during the anticancer treatments, was able to partially restore antioxidant parameters and improve markers of hepatic function compared to the groups exposed to doxorubicin and/or irradiation alone.

The antioxidant properties of nigella could help protect certain healthy tissues from treatment-induced oxidative damage, once again demonstrated exclusively in animal studies.

If data from cellular and animal models suggest a protective potential of black seed oil against certain toxic effects of chemotherapy and radiotherapy, only clinical studies can assess their relevance under real-world conditions. To date, clinical research remains limited, but two studies merit closer examination.

• A first clinical study investigated the effect of oral supplementation with Nigella sativa in patients with lung cancer undergoing chemotherapy. Twenty-one patients were allocated into two groups: one receiving chemotherapy alone, the other receiving chemotherapy combined with Nigella sativa supplementation (2 × 500 mg per day for nine weeks). The researchers assessed changes in interferon-γ (IFN-γ) levels, a cytokine involved in the immune response. The results show a significantly greater increase in IFN-γ levels in the nigella-supplemented group compared to the control group, suggesting stimulation of certain immune components. These findings indicate a potential immunomodulatory effect of nigella in patients receiving chemotherapy.

• A second clinical study focused on the adverse skin effects of radiotherapy, particularly acute radiation dermatitis, characterized by redness, scaling, and blisters, in breast cancer patients. Sixty-two patients were randomly assigned to two groups to receive either a gel containing 5% extract of Nigella sativa or a placebo, applied twice daily for the entire duration of radiotherapy. The results show that patients treated with the nigella-based gel developed acute radiation dermatitis less frequently. Additionally, the reported intensity of skin pain was lower in the nigella group. However, no significant effect was observed on overall quality of life, suggesting a targeted but partial benefit.

Available clinical evidence suggests that Nigella sativa may, in certain contexts, contribute to alleviating some of the side effects of anticancer treatments.

However, despite these encouraging results, several major limitations must be highlighted. These studies involve small sample sizes, limited follow-up durations, and employ various forms of Nigella sativa (oral supplements, topical extracts), which complicates comparisons. Moreover, these data do not support conclusions about the safety of routine nigella use in the cancer setting, particularly given the potential interactions with anticancer therapies that remain insufficiently studied.

These results remain insufficient to recommend the widespread use of black seed in cancer patients. Any topical application or oral intake of black seed oil during chemotherapy or radiotherapy must necessarily be undertaken under medical supervision, in order to avoid adverse effects or deleterious interactions with the treatments.

• CUOMO A. & al. Role of Nigella sativa and its constituent thymoquinone on chemotherapy-induced nephrotoxicity: Evidences from experimental animal studies. Nutrients (2017).

• KHAN F. & al. Protective effect of Nigella sativa oil on cisplatin induced nephrotoxicity and oxidative damage in rat kidney. Biomedicine & Pharmacotherapy (2017).

• MAHAM M. & al. Nigella sativa L. for prevention of acute radiation dermatitis in breast cancer: A randomized, double-blind, placebo-controlled, clinical trial. Complementary Therapies in Medicine (2019).

• EL-SHARKAWY M. A. & al. Nigella sativa seeds extract ameliorates toxicity induced by doxorubicin and gamma radiation in rats. Egyptian Academic Journal of Biological Sciences (2020).

• TEPPER J. E. & al. Radiation therapy-associated toxicity: Etiology, management, and prevention. CA: A Cancer Journal for Clinicians (2021).

• CIANCIOSI D. & al. Nutritional value and preventive role of Nigella sativa L. and its main component thymoquinone in cancer: An evidenced-based review of preclinical and clinical studies. Molecules (2021).

• BRIANNA H. & al. Chemotherapy: How to reduce its adverse effects while maintaining the potency? Medical Oncology (2023).

• BURNET N. G. & al. The use of radiotherapy, surgery and chemotherapy in the curative treatment of cancer: results from the FORTY (Favourable Outcomes from RadioTherapY) project. British Journal of Radiology (2023).

• RASHID S. & al. Nigella sativa averts 5-fluorouracil induced kidney injury via targeting redox imbalance and MAPK pathway. Indian Journal of Pharmaceutical Education and Research (2024).

• RAHMA S. & al. The influence of Nigella sativa on the increase of IFN-γ and quality of life in lung cancer patients undergoing chemotherapy. Journal of Respirology (2025).