Introduction: In breast cancer patients, menopausal symptoms are often reached earlier and in a more severe manner than in healthy women. They can dramatically reduce a patient’s quality of life. Treatment for breast cancer patients remains difficult due to hormone replacement therapy being contraindicated. Therefore, treatment alternatives like herbal phytoestrogen preparations are considered to be a treatment option. Methods: All randomized controlled trials (RCTs) that investigated comparisons of food products, extracts, or dietary supplements containing phytoestrogens in women with a diagnosis of breast cancer were included in the analysis. Results: There was no evidence that phytoestrogen preparations had a benefit over placebo in the treatment of breast cancer patients with menopausal symptoms. Neither the frequency nor severity of menopausal symptoms and the quality of life or occurrence of adverse events were reduced in comparison to a placebo. Conclusion: As we cannot prove a benefit of plant extracts in the treatment of menopausal symptoms in breast cancer patients, different herbal preparations should be analyzed in RCTs in order to find sufficient and safe new treatment options for symptomatic menopausal breast cancer patients. A focus should also be laid on developing a core outcome set to simplify pooling of different studies.