Chemotherapy, radiotherapy… could Nigella sativa oil help patients better tolerate cancer treatments?

Chemotherapy and radiotherapy are pillars of cancer treatment. While they have significantly improved patient survival, they are also accompanied by sometimes considerable side effects.

Chemotherapy is based on the administration of cytotoxic drugs intended 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 works by targeting rapidly dividing cells, a hallmark of tumour cells. However, this mechanism is not exclusive to malignant cells: certain healthy cells, such as those in hair follicles, bone marrow, the digestive mucosa or the nervous system, also renew rapidly. This lack of specificity accounts for much of the observed side effects, including hair loss, nausea and vomiting, intense fatigue, digestive disturbances, peripheral neuropathies, cardiovascular complications and even transient cognitive disturbances.

Radiotherapy, for its part, employs ionising radiation to destroy tumour cells by inducing DNA damage that prevents them from dividing. However, once again, the effects of radiation are not confined to cancerous cells: healthy tissues adjacent to the irradiated area can also be affected. Adverse effects depend on the dose delivered, the organ involved and the individual patient’s characteristics. They may manifest acutely, such as skin reactions, mucosal inflammation or marked fatigue, or arise later in the form of fibrosis or functional impairments. Technological advances have improved tumour targeting and reduced exposure of healthy tissues, but radiotherapy-related toxicity remains a central challenge in oncological care.

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

These studies remain largely experimental, but they provide valuable insights into the potential mechanisms at play. Several animal studies show that administration of oil or extracts of Nigella sativa may reduce chemotherapy-induced renal toxicity, particularly cisplatin, but also methotrexate, doxorubicin or 5-fluorouracil. These anticancer agents are known to generate a significant production of reactive oxygen species, leading to oxidative damage in renal cells.

In these experimental models, nigella and thymoquinone reduce lipid peroxidation, enhance the activity of endogenous antioxidant enzymes, such as superoxide dismutase and catalase, and improve biological markers of renal function. At the histological level, a reduction in renal tissue lesions is also observed when nigella oil is administered before and after exposure to chemotherapeutic agents.

Beyond the kidney, some studies suggest a broader hepatoprotective and antioxidant effect of the nigella. Extracts of seeds of Nigella sativa have notably demonstrated an ability to attenuate the oxidative stress and hepatic damage induced by doxorubicin or by exposure to gamma radiation. These findings suggest that the antioxidant properties of thymoquinone may contribute, in certain experimental contexts, to protecting healthy tissues from collateral damage associated with treatments, without directly interfering with their cytotoxic action on tumour cells.

One example comes from a study conducted on rats. The animals received a single dose of cisplatin (6 mg/kg), which induced acute kidney injury via a massive production of free radicals. Oral administration of Nigella sativa oil (2 mL/kg), before and after chemotherapy, helped to limit the elevation of biological markers of renal insufficiency, notably serum creatinine and blood urea. At the cellular level, Nigella sativa oil preserved the activity of enzymes responsible for proper kidney tubule function, as well as those involved in carbohydrate metabolism. These biochemical findings are corroborated by histological analysis, which shows severe renal lesions in animals treated with cisplatin alone, compared with markedly attenuated damage in the group co-treated with Nigella sativa oil.

Taken together, the data suggest a protective role for nigella against oxidative stress and chemotherapy-induced renal tissue damage in a preclinical context.

Another experimental study examined the ability of a nigella seed extract to mitigate the combined toxicity of doxorubicin and radiotherapy. In this protocol, rats received either doxorubicin alone, gamma irradiation alone, or both over several weeks, inducing marked oxidative stress and impaired liver function. These treatments led to a significant decrease in endogenous antioxidant defences, coupled with increased lipid peroxidation markers and disruptions of hepatic enzymes. Daily oral administration of a nigella seed extract (2 g/kg), begun before and continued throughout the anticancer treatments, enabled partial restoration of antioxidant parameters and improvements in markers of liver function compared with the groups exposed only to doxorubicin and/or irradiation.

The antioxidant properties of nigella may help protect certain healthy tissues from treatment-induced oxidative damage, once again in strictly animal models.

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

• An initial clinical trial examined the effect of oral supplementation with Nigella sativa in patients with lung cancer receiving chemotherapy. Twenty-one patients were allocated into two groups: one received chemotherapy alone, the other chemotherapy combined with supplementation of Nigella sativa (500 mg twice daily for nine weeks). The researchers evaluated changes in interferon-γ (IFN-γ) levels, a cytokine pivotal to the immune response. The results show a significantly greater increase in IFN-γ levels in the group supplemented with Nigella sativa compared with the control group, suggesting stimulation of certain immune components. These data indicate a potential immunomodulatory effect of Nigella sativa in patients undergoing chemotherapy.

• A second clinical study focused on the adverse cutaneous effects of radiotherapy, particularly acute radiation dermatitis, characterised by erythema, scaling and blistering, in female breast cancer patients. Sixty-two patients were randomised into two groups to receive either a gel containing 5% extract of Nigella sativa, or a placebo, applied twice daily throughout the entire radiotherapy course. The results show that patients treated with the nigella-based gel developed acute radiation dermatitis less frequently. Moreover, the reported severity of skin pain was lower in the nigella group. In contrast, no significant effect was observed on overall quality of life, suggesting a targeted but partial benefit.

The available clinical evidence suggests that Nigella sativa could, in certain contexts, help alleviate some of the side effects of anticancer treatments.

However, despite these encouraging findings, several significant limitations must be highlighted. These studies involve small sample sizes, short follow-up periods, and employ different forms of Nigella sativa (oral supplement, topical extract), which complicates comparisons. Moreover, these data do not allow for conclusions regarding the safety of systematic nigella use in a cancer context, particularly due to potential interactions with anticancer treatments, which remain insufficiently studied.

These findings remain insufficient to recommend the widespread use of nigella in patients with cancer. Any topical application or oral intake of nigella oil during chemotherapy or radiotherapy must be carried out strictly under medical supervision, to avoid adverse effects or deleterious interactions with 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).