Mistletoe is typically given by subcutaneous injection, but it sometimes is injected directly into the tumor particularly on the liver, esophagus and cervix. It may also be taken orally in tumors of the brain and spinal cord. The best results with Iscador are claimed for its use with solid tumors both before and after surgery and radiation. Given 10 to 14 days before surgery, it is thought to help prevent metastatic spread due to surgery and to promote recovery and it is also used for advanced stage, inoperable solid tumors, especially cancers of the bladder, stomach, intestine, genital organs, and skin. It is also claimed that bone metastases are retarded in some cases.
Results appear less promising for inoperable cancers of the breast, lungs and esophagus.
It is thought that tumor growth slows or stops, and then gradual regression begins. It is believed that tumor cells are transformed first to a semi-malignant form, then to chronic inflammation and finally to normal tissue. Mistletoe contains a cytotoxic lectin, viscumin. Various lectins are both cytotoxic and immunostimulatory. It usually produces an increase in body temperature and flu-like symptoms.