European mistletoe has been used to treat a wide variety of physical and mental conditions. It is best known as an additional treatment with other drugs for treating cancer.

Mistletoe extract may treat bladder cancer
After surgery for superficial bladder cancer, treatment with a mistletoe extract appears to be effective at reducing tumor recurrence. Mistletoe extracts have been shown to act favorably on proteins that affect cancer and have been widely used for many years as alternative therapy in patients with malignancies. In the current study, 30 patients with superficial bladder carcinoma received six weekly instillations of a standardized water-based mistletoe extract beginning about 4 weeks after surgery. The treatment was well tolerated at all concentrations and there were no reports of side effects.
At 12 months, nine tumors had recurred. In the 24 patients with so-called pTa G2 and pT1 G2 tumors, the recurrence rate was 33 percent, comparable to the recurrence rate in similar historical controls treated with BCG, the investigators point out.

Adjuvant intravesical treatment of superficial bladder cancer with a standardized mistletoe extract.
J Urol. 2005.
Adjuvant intravesical immunotherapy with bacillus Calmette-Guerin (BCG) for noninvasive superficial bladder cancer has been shown to decrease tumor recurrence significantly. However, serious local and systemic side effects of this treatment have promoted the use of other immunoactive substances, which to date have failed to show efficacy equal to that of BCG immunotherapy. In the current phase I/II clinical trial an aqueous mistletoe extract standardized to mistletoe lectin was administered intravesically to 30 patients with superficial urothelial bladder carcinoma. About 4 weeks after transurethral resection each patient received 6 instillations at weekly intervals of 50 ml extract with mistletoe lectin concentrations between 10 and 5,000 ng/ml, which was retained in the bladder for 2 hours. Three patients per group received a dose, which was then doubled in the next group. Clinical followup consisted of examinations with cystoscopy, cytology and random biopsies. To detect cytokines and tumor necrosis factor-p75 receptor venous blood and urine samples were taken before instillation, and 2, 6 and 24 hours thereafter. From these results it is concluded that standardized mistletoe extract could be a potential alternative adjuvant therapy for superficial bladder cancer. Nevertheless, the optimal intravesical treatment regimen has yet to be defined.

Perm J. 2015. High-Dose Viscum album Extract Treatment in the Prevention of Recurrent Bladder Cancer: A Retrospective Case Series. High-dose Viscum album treatment may have interrupted frequently recurring tumors in individual patients with recurrent bladder cancer. Prospective studies are needed to assess whether this treatment offers an additional, bladder-sparing preventive option for patients with intermediate- to high-risk nonmuscle-invasive bladder cancer. Treatment was generally well tolerated and no patient stopped treatment because of side effects.

Pancreatic cancer
Integr Cancer Ther. Dec 2013. Mistletoe (Viscum album) Therapy in Patients With Unresectable Pancreas Carcinoma: A Retrospective Analysis. Intratumoral mistletoe application has induced local tumor response in various cancer entities. This off-label use needs to be validated carefully in terms of safety and benefits. Here we report on 39 patients with advanced, inoperable pancreatic cancer, who received in total 223 intratumoral applications of mistletoe, endoscopic ultrasound guided or under transabdominal ultrasound control. No severe procedure-related events were reported. Adverse drug reactions were mainly increased body temperature or fever in 11% and 14% of the applications, respectively. Other adverse drug reactions, such as pain or nausea, occurred in less than 7% of the procedures. No severe adverse drug reaction was recorded. Patients received standard first- and second-line chemotherapy and underwent adequate palliative surgical interventions as well as additive subcutaneous and partly intravenous mistletoe application. A median survival of 11 months was observed for all patients, or 11.8 and 8.3 months for stages III and IV, respectively. Due to the multimodal therapeutic setting and the lack of a control group, the effect of intratumoral mistletoe administration alone remains unclear. This retrospective analysis suggests that intratumoral-applicated mistletoe might contribute to improve survival of patients with pancreatic cancer.

BMC Complement Altern Med. Jan 2014. Interaction of standardized mistletoe (Viscum album) extracts with chemotherapeutic drugs regarding cytostatic and cytotoxic effects in vitro. Given the importance of complementary and alternative medicine (CAM) to cancer patients, there is an increasing need to learn more about possible interactions between CAM and anticancer drugs. Mistletoe (Viscum album L.) belongs to the medicinal herbs that are used as supportive care during chemotherapy. In the in vitro study presented here the effect of standardized mistletoe preparations on the cytostatic and cytotoxic activity of several common conventional chemotherapeutic drugs was investigated using different cancer cell lines. uman breast carcinoma cell lines HCC1937 and HCC1143 were treated with doxorubicin hydrochloride, pancreas adenocarcinoma cell line PA-TU-8902 with gemcitabine hydrochloride, prostate carcinoma cell line DU145 with docetaxel and mitoxantrone hydrochloride and lung carcinoma cell line NCI-H460 was treated with docetaxel and cisplatin. Each dose of the respective chemotherapeutic drug was combined with Viscum album extract (VAE) in clinically relevant concentrations and proliferation and apoptosis were measured. VAE did not inhibit chemotherapy induced cytostasis and cytotoxicity in any of our experimental settings. At higher concentrations VAE showed an additive inhibitory effect. Our in vitro results suggest that no risk of safety by herb drug interactions has to be expected from the exposition of cancer cells to chemotherapeutic drugs and VAE simultaneously.

Blood sugar
Evaluation of the hypoglycemic effect and antioxidant activity of three Viscum album subspecies (European mistletoe) in streptozotocin-diabetic rats.
J Ethnopharmacol. 2005.
The acute hypoglycaemic effect of water and ethanolic extracts of three Viscum album subspecies, ssp. album, ssp. austriacum, ssp. abietis, were investigated in normoglycaemic and streptozotozocin-induced diabetic rats. The findings obtained in the experiments demonstrated that European mistletoe subspecies possess potent antihyperglycaemic and antioxidant activity depending on host plant.

Blood vessel dilation
Vasodilator activity of the aqueous extract of Viscum album.
Fitoterapia. 2005.
The aqueous extract of mistletoe leaves showed a significant coronary vasodilator activity on the Langendorff's isolated and perfused heart model. The data obtained suggest that the aqueous extract of mistletoe contains some biologically active principles that may act as inducers of the nitric oxide/soluble guanylate cyclase pathway.

Other uses
Asian-Australas J Anim Sci. 2016. Ethanol Extracts from Mistletoe (Viscum album L.) Act as Natural Antioxidants and Antimicrobial Agents in Uncooked Pork Patties during Refrigerated Storage.