Rosemary (Rosmarinus officinalis) is a culinary herb in the mint family with strong antioxidant, anti-inflammatory, and insecticidal properties. Rosemary contains a variety of volatile oils, most prominently rosmarinic acid, carnosic acid and ursolic acid, which give the herb its characteristic scent and flavor. Rosemary is also a dietary source of luteolin.

Breast cancer-related effects of eating rosemary

Rosemary extract and breast cancer

While there are a multitude of studies pertaining to the micronutrients in rosemary, fewer studies have attempted to address the chemopreventive potential of rosemary as a whole food. Most of these studies have focused on the impact of rosemary on triple negative (ER-/PR-/HER2-) breast cancer growth and survival. However, rosemary has also been shown to inhibit hormone receptor positive (ER+/PR+) breast cancer.
One 2025 study reported that treatment with an extract of rosemary leaves resulted in anti-proliferative and cytotoxic effects in both triple negative and ER+/PR+ breast cancer cells in a dose-dependent manner. Another study demonstrated that rosemary extract inhibited triple negative cell proliferation and survival in part by modulating key signaling molecules involved in cell proliferation and apoptosis (programmed cell death).
Rosemary extract has also been reported to sensitize triple negative breast cancer cells to treatment with cisplatin and Taxol (paclitaxel), increasing their cytotoxic effects.

Rosmarinic Acid

Rosmarinic acid has been shown to inhibit proliferation and induce apoptosis of both triple negative and ER+/PR+ breast cancer cells. Rosmarinic acid has also been reported to reduce the viability and migration of triple negative breast cancer stem cells. In addition, rosmarinic acid has been demonstrated to inhibit the migration of bone-homing breast cancer cells in a dose-dependent manner.
Rosmarinic acid has also been reported to enhance the treatment effects of the chemotherapy drugs Adriamycin (doxorubicin), cisplatin, 5-FU, Taxol and Taxotere (docetaxel). In addition, rosmarinic acid has been demonstrated to reduce Adriamycin-induced cardiomyopathy without reducing its cytotoxic effects against ER+/PR+ breast cancer cells.

Carnosic acid

Carnosic acid is a phenolic diterpene specific to the Lamiaceae (mint) family; carnosol is the product of oxidative degradation of carnosic acid. Lamiaceae plants typically incorporate both carnosic acid and carnosol; carnosic acid predominates in rosemary.
Carnosic acid has been reported to act on key pathways and proteins regulating the cell cycle, growth, invasion, and metastasis of triple negative breast cancer cells. Carnosic acid has also been demonstrated to increase apoptosis (by upregulating pro-apoptotic genes and downregulating anti-apoptotic genes) in both ER+/PR+ and triple negative breast cancer cells in a dose-dependent manner while not harming normal breast cells. In addition, carnosic acid has been reported to enhance the cytotoxic treatment effects of tamoxifen in ER+/PR+ cells. One study also found that carnosic acid enhanced the treatment effects of Herceptin in HER2+ breast cancer cells.

Ursolic acid

Ursolic acid has been shown to inhibit tumor formation and growth in all of the major breast cancer receptor types (ER+/PR+, HER2+ and triple negative). Ursolic acid has also been shown to reverse multidrug resistance in breast cancer cells. For example, one study found that ursolic acid reversed resistance to Taxol in Taxol-resistant triple negative breast cancer. Another study reported that ursolic acid resensitized multidrug resistant ER+/PR+ breast cancer cells to Adriamycin. Still another study demonstrated that ursolic acid increased the sensitivity of triple negative breast cancer cells to Adriamycin.

Additional comments

Rosemary should be consumed in moderation. Based on the available evidence, the amounts of rosemary normally used as a herb in food are safe. However rosemary oil in medicinal amounts has the potential to cause kidney and liver damage, as well as harm to the reproductive system. Note that even organic rosemary can incorporate meaningful levels of heavy metals such as lead.

Sources of information provided in this webpage

The information above, which is updated continually as new research becomes available, has been developed based solely on the results of academic studies. Clicking on any of the underlined terms will take you to its tag or webpage, which contain more extensive information.
Below are links to 20 recent studies concerning this food and its components. For a more complete list, including less recent studies, please click on rosemary.