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Herbal Medicine and Cancer

By Ming-Yee Pang



Cancer is the second most common cause of death in the United States. The American Cancer Society (ACS) estimates that half the men and one-third of the women in the United States will develop cancer in their lifetimes. The ACS also estimates that about 1.4 million Americans will be diagnosed with cancer in 2006, and about 565,000 people will die of the disease. ( Of these new patients, more than 50% will participate in some forms of alternative therapy. One of the most common alternative therapies for cancer is herbal medicine. A national survey found that 14% of all people in the United States are using herbal medicine, yet more than 70% of these people do not tell their physicians about what they are taking. ( This figure is worrisome because the safety and effectiveness of herbal medicine is still not fully understood.


Origins of Herbal Medicine


How Does Herbal Medicine Work?





·         In addition, herbs may be used as an adjunctive treatment for cancer. Chemotherapy and radiation therapy are the two most common treatments for cancer in conventional medicine. Chemotherapy is treatment of cancer with drugs that destroy cancer cells. However, since chemotherapy target all rapidly dividing cells and are not specific for cancer cells, they can harm healthy tissue as well. There are also many side effects when undergoing chemotherapy, including nausea, fatigue, hair loss, etc. Thus, chemotherapy could be very harsh on the patient’s body. Likewise, radiation therapy is hard on the body as well. Using radiation to kill cancer cells, radiation sometimes also damages normal cells. Moreover, patients who are undergoing radiation therapy suffer from tremendous hair loss and other side effects. As a result, herbs may be used as a supplemental treatment to offset the damaging side-effects of conventional cancer treatments. They may also be used to strengthen the patient’s immune system which is often weaken by the ongoing and invasive radiation therapy and chemotherapy. (


Common Types of Herbal Medicine

Herbs can be used fresh, dried, or as alcohol or water extracts. The most common forms available include teas, tinctures, extracts, capsules/tablets, powders, and ointments.

·         Teas                                                          

Herbal medicine is traditionally taken in tea form. It is thought that human body absorbs tea easily and quickly so it is the most commonly used method. Teas are generally prepared by boiling the leaves, roots, and flowers of a medicinal plant in hot water.

·         Tinctures

In a tincture, alcohol is used to extract the active ingredients of an herb. Alcohol is also a very effective natural preservative. Thus, tincture can be stored for a long period of time. Tinctures are concentrated and cost-effective.

·         Extracts

Extracts usually come in a liquid form, but solid extracts are also available. They can be made with either alcohol or water. They are the most concentrated form of herbal treatment, but have a stronger herbal taste.

·         Capsules and Tablets                                                                 

Herbs are dried and grinded into powders. Then, powders are compressed or put in an empty pill coating to form capsules and tablets. They tend to be less strong and potent than tinctures and extracts. However, they often contain a standard level of active components.

·         Ointments

Herbs can also be made into ointments for topical use.

Why Do People Take Herbal Medicine?

·         People who take herbal medicine generally believe that herbs are natural; therefore they must be harmless (Brigden, 1995).

·         Another myth is that chemicals produced in nature are better than the same products synthesized in chemical laboratories (Brigden, 1995).

·         Herbal medicine has a much lower cost than conventional drugs and other medical procedures. Therefore, herbal medicine attracts patients with poor medical insurance coverage (Spaulding-Albright, 1997).

·         People with terminal diseases are also more willing to take herbal medicine or engage in other alternative treatments that can provide them with a possibility of improving quality and quantity of life (Spaulding-Albright, 1997).

·         There is a growing distrust in traditional medicine and physicians. In conventional medicine, physicians generally focus on treating the symptoms of illnesses Such approach often makes patients feel that they are being treated as a non-person, and that they do not have control over their health conditions. Some patients might thereby look for a more holistic approach, such as herbal medicine, which treats patients as a whole person. It also provides patients with a sense of control over their disease processes (Spaulding-Albright, 1997).

Evidences on Some of the Herbal Treatments for Cancer:

·       PC-SPES


Claim: To treat prostate cancer


Research evidence:


PC-SPES is a recently developed herbal supplement for the treatment for prostate cancer. It consists of eight different plant extract. A number of Phase II studies have been conducted on PC-SPES. The largest and most carefully-controlled study to date is a Phase II trial of PC-SPES in 70 patients with advanced prostate cancer: 33 patients with androgen-dependent prostate cancer and 37 patients with androgen-independent prostate cancer (Small, E. J., Frohlich, M. W., Bok, R., Shinohara, K., Grossfield, G., Rozenblat, Z., Kelly, W. K., Corry, M., & Reese, D. M., 2000). All participants were not allowed to receive any new therapy within 30 days of study entry, including the use of chemotherapy, hormonal agents, therapeutic agents, and herbal supplements. Patients first received 320-mg capsules for one week. Of there were no adverse reactions to the capsules, the dose was increased to 640-mg for a week, and then to the maximum dose of 960-mg, which was equivalent to 9 capsules daily. The goals of this study were to examine the effect of PC-SPES on Prostate specific antigen (PSA) levels in cancer patients, as well as the toxicity of PC-SPES. Clinical outcome was assessed with PSA level measurement and imaging studies. A response was defined as a reduction PSA levels greater than 50% from baseline. All 32 patients with androgen-dependent prostate cancer experienced PSA declines of greater than 80%; no patient had developed PSA progression 64 weeks after treatment. Over half of the patients with androgen-independent prostate cancer had a PSA decline of greater than 50%; they developed PSA progression in a median time of 16 weeks. Although drop in PSA levels was a good sign, imaging studies (positive bone scans) showed that only 2 patients had tumor shrinkage. This indicated that PC-SPES was not an effective cancer treatment. In addition, Small and his colleagues (2000) found that PC-SPES was associated with a number of endocrine-side effects. All patients reported a decrease in sex drive on therapy. 15 patients who could achieve erection before therapy lost the ability to do so. PC-SPES also led to the abnormal enlargement of breasts in all patients and hot flashes in about one-third of patients.


Although several clinical trials showed that PC-SPES could lower PSA levels, none showed that it could shrink prostate tumors or prolong survival in men with prostate cancer. In addition, PC-SPES was taken off the market because of contamination in 2002. (


·       Huanglian      

Some of it claims:


o       To treat cancer

o       To treat bacterial and viral infections

o       To treat respiratory and ear infections

o       To treat gastrointestinal problems


Research evidence on its efficacy as a cancer treatment:


Huanglian, also known as Coptis chinensis, is an herb that is widely used in China for inflammatory conditions and gastroenteritis. Its anti-cancer activity has been demonstrated in previous studies. To further examine its role as an anti-cancer agent, Li, X-K., Motwani, M., Tong, W., Bornmann, W., & Schwartz, G. K. (2000) conducted an in-vitro study on Huanglian’s effects on tumor cell growth. In this study, human gastric cancer cell lines, breast cancer cell lines, as well as colon cancer cell lines were cultured using standard protocol. Cell cultures were randomly plated onto 6-well plates and treated with drug free media (control), or media containing 1, 10, or of huanglian for five days. Cell density was measured at day 0 (without huanglian) and at each of the following five days. Li et al. (2000) found that huanglian completely inhibited the growth of gastric, breast, and colon cancer cell lines after 3 consecutive days of exposure of 10ug/ml of huanglian. The effect of hunaglian on tumor cell growth was associated with selective suppression of cyclin B1 protein, which resulted in the inhibition of cdc2 kinase activity – a target for cancer chemotherapy (Li, Motwani, Tong, Bornmann, & Schwartz, 2000).


Despite encouraging results, in-vitro could not accurately reflect the safety and efficacy of herbal medicine in human bodies. Hence, a well-controlled clinical trial is required to study the effects of huanglian on human body, as well as any adverse effect associated with the use of huanglian. In fact, a Phase I of huanglian on tumor is currently underway at Memorial Sloan-Kettering Cancer Center (



Some of its claims:



Research evidence on its efficacy as a cancer treatment:



Baikal skullcap, also known as Scutellaria Baicalensis, is derived from the root of the plant. The herb has been used in traditional Chinese medicine to treat a variety of conditions. The flavonoid components of Baikal skullcap are thought responsible for its anti-cancer activity. An in-vitro study was conducted by Scheck, Perry, Hank, & Clark (2006) to study the anti-cancer effects of Baikal skullcap. In this study, cell lines grown from primary and recurrent brain tumors from three patients were cultured. Cells that were resistant to the chemotherapeutic agent 1,3-bis (2-chloroethyl)-1 nitrosourea (BCNU) were used to identify effects of Baikal skullcap when used alone and in conjunction with BCNU: They were treated with either 2.5 ug/ml of BCNU alone, 50ug/ml of Baikal skullcap alone, or a combination of both. Cells were treated for 3 consecutive days. Results were compared to control (untreated) cells. The results of this study showed that the anticancer activity of Baikal skullcap was evident as it inhibited cell growth in all brain tumor cell lines; it also increased its inhibitory effect when used in conjunction with BCNU.  Hence, results of this study support the efficacy of Baikal skullcap as an anticancer agent for brain tumors, and also as a potential supplementary treatment to current chemotherapeutic drugs, such as BCNU, in treating brain tumors (Scheck, Perry, Hank, & Clark, 2006).


Nonetheless, Baikal skullcap has not been studied in clinical trials as a single agent. Thus, it must be used with caution.



Some of its claims:



Research evidence on its efficacy as a cancer treatment:


Astragalus, also known as Huang chi, has been widely used in China to stimulate the immune system. Researchers at the University of Texas Medical Center conducted an in-vitro study in which they found that Astragalus improved the immune system in 13 cancer patients by 260% compared with untreated cells and by 160% compared with cells from healthy controls. In spite of this promising result, other studies showed that Astragalus could cause low blood pressures, dizziness, and fatigue; overdoses could even damage the immune system (Chu, Wong, & Mavlight, 1988, cited in Spaulding-Albright, 1997).


In a clinical trial that was designed to test whether Astragalus had an effect on human immune system, 31 patients with end-stage kidney diseases were randomized into two groups: the treatment group received Astragalus extract for two months, and the other group received a placebo for two months. Compared to the placebo group, the Astragalus group had significantly higher levels of IL-2, a substance that stimulates the growth of immune cells and their response to disease. However, this study did not address whether Astragalus helped patients to fight off cancer or prolonged patients’ lives (Qun, Luo, Zhang, Chen, Zhang, Lin, 1999)



Some of its claims:



Research evidence of its efficacy as a cancer treatment:


Herbal tea Essiac has been promoted as a cure for all cancers since 1992, but there is very little evidence to support its efficacy as a cancer treatment. In laboratory experiments, rhubarb, one of the constituents in Essiac, was demonstrated to cause tumor death in mice, but these effects have not been shown in humans in the United States, In a Canadian study of 77 cancer patients taking the herbal treatment, only eight improved their conditions; 17 died; 47 showed no effects. On the follow-up of the eight patients who showed improved conditions, three of them developed tumor progression, two of them died, and three remained stable. (US Government Printing Office, 1990, cited in Spaulding-Albright, 1997)



Claim: To treat cancer


Research Evidence:


Found in the seeds of apricots, peaches, and plums, Laetrile gained its popularity as an alternative cancer treatment. Nonetheless, in a clinical trial, 178 cancer patients were treated with amygdalin (Laetrile). None of the patients were in preterminal condition before the study, and one-third of them had not received any prior treatment. Patients were received amygdalin treatment three times a day for 21 days. In addition, patients were placed on a metabolic therapy consisting of diet, vitamins, minerals, and pancreatic enzyme supplementation. Of all patients, there was only one partial response, 79% developed cancer progression after two months and 91% by three months. Median survival was 4.8 months from initiation of therapy. In fact, 85% of the participants died within 8 months from the start of the study. Many adverse effects were also detected, including cyanide toxicity, headache, nausea, vomiting, dizziness, and mental obtundation. The results suggest that amygdalin is ineffective in the treatment of cancer. (Moertel, Fleming, Rubin, Kvols, Sarna, Koch, Currie, Young, Jones, & Davignon, 1982)



Some of its claims:



Research evidence on its efficacy as a cancer treatment:


There has been a fair amount of randomized clinical trials done on mistletoe in Europe. In order to investigate whether or not these clinical trials demonstrated the efficacy of mistletoe as a cancer therapy, Ernst, Schmidt, & Steuer-Vogt (2003) conducted a systematic review of these trials. In reviewing ten controlled clinical trials, researchers found that most of them were poorly designed. While some of the weaker studies reported benefits of mistletoe in treating cancer, all of the rigorous studies with stronger methodology and designs failed to demonstrate efficacy of mistletoe therapy.


For example, in one of the clinical trials reviewed, Douwes and colleagues (1986) randomized 60 patients with metastatic colorectal carcinoma into three groups: Group A was treated with chemotherapy only; Group B was treated with both chemotherapy and mistletoe extracts; Group C was treated with chemotherapy and xenogenic peptides (cited in Ernst, Schmidt, & Steuer-Vogt, 2003). Researchers found that the mean survival time in groups A and B were about twice that of group C. However, this trial was not patient-blinded. In addition, the amount of xenogenic peptides injected, as well as the number of chemotherapy cycles given to each group, were not reported. Hence, no sound conclusion could be drawn from this study.


In another clinical trial, Salzer et al. (1991) randomized 218 patients with bronchial cancer into two groups: Group A received mistletoe extracts and group B received no extracts (cited in Ernst, Schmidt, & Steuer-Vogt, 2003). Both groups received conventional treatments. Although the author stated that efficacy of Mistletoe in treatment of cancer was clinically significant, results from this study was not statistically significant. In addition, this report provided little details on the methods used in this study.


In a more rigorous trial, Steuer-Vogt and colleagues (2001) studied a total of 477 patients with head and neck squamous cell carcinoma. Patients in the experimental group received injections of a mistletoe extract twice a week for 12 weeks, and then patients received no mistletoe for 4 weeks (cited in Ernst, Schmidt, & Steuer-Vogt, 2003). Three of the same cycles were given in total. Researchers found that the use of mistletoe had no effect in the treatment of head and neck squamous cell carcinoma. Ernst, Schmidt, & Steuer-Vogt (2003) stated that this was the most rigorous study evaluated in this systematic review. Nonetheless, it was neither placebo-controlled nor double-blind.


Overall, most of the clinical trials studying the effectiveness of mistletoe as a cancer treatment have been poorly designed or lack a placebo group. Therefore, it is still uncertain whether mistletoe works.


Are Herbal Medicine Safe?


As mentioned before, many people perceive herbal medicine as safe because of its natural appeal. Nevertheless, that is just a myth. Almost all herbal medicines used in the United States are classified as “dietary supplements”. Hence, there is no strict regulation on herbal medicine. For instance, manufacturers are not required to demonstrate either the effectiveness or the safety of herbal medicines before they are sold. If an herbal medicine is unsafe, it is the job of the U.S. Food and Drug Administration (FDA) to prove this claim. Therefore, herbal medicine is less regulated than conventional medicine (Spaulding-Albright, 1997)


Problems with herbal medicine include:


1. Since herbal preparations are not strictly regulated, the quality and quantity of active ingredients in an herbal product might vary between manufacturers.


2. Herbal medicine maybe contaminated or adulterated. In Belgium, Aristolochia fangchi was misidentified as Stephania tetrandra. Patients who were given Aristolochia fangchi as a weight loss supplement developed severe kidney failure (Gottlieb, 2000).


3. Herbal remedies can interact with other pharmaceutical products, such as anticancer drugs. They can also hinder or interfere with the effects of other conventional treatments.


4. Life-threatening side effects are occasionally associated with used of herbs. For example, Ephedra, also known as Ma huang, was banned by the FDA due to reports of severe adverse effects, including stroke and death (





In conclusion, the effectiveness of herbal medicine as a treatment for cancer is not well-understood yet. Although many world-wide websites claim the efficacy of herbal medicine as a cancer treatment, there is a lack of strong evidence from clinical trials. Without consistent evidences that come from well-designed, carefully-controlled, randomized, double-blind, clinical trials, it is very difficult to assess the safety and efficacy of herbal medicine. Therefore, cancer patients should be careful when they choose to use herbal medicine. They should also inform their health care providers about all of the herbal medicines they are taking in case these medicines might interact with other cancer treatments. Meanwhile, researchers should continue to conduct properly controlled clinical trial to examine the safety and efficacy of herbal medicine as a potential cancer therapy.




Brigden, M. L. (1995). Unproven (Questionable) Cancer Therapies. Western Journal of Medicine, 163, 463-469.


Ernst, E., Schmidt, K., & Steuer-Vogt, M. K. (2003). Mistletoe for cancer? A systematic review of randomized clinical trials. International Journal of Medicine, 107, 262-267.


Gottlieb, S. (2000). Chinese herb may cause cancer. British Medical Journal, 320, 1623.


Qun, L., Luo, Q., Zhang, Z. Y., Chen Y. C., Zhang, J. B., Lin, D. H. (1999). Effects of astragalus on IL-2/IL-2R system in patients with maintained hemodialysis.

          Clinical Nephrology, 52(5), 333-334


Li, X-K., Motwani, M., Tong, W., Bornmann, W., & Schwartz, G. K. (2000). Huanglian, A Chinese herbal extract, inhibits cell growth by suppressing the expression of cyclin B1

          And inhibiting CDC2 kinase activity in human cancer cells. Molecular Pharmacology, 58, 1287-1293.


Moertel, C. G., Fleming, T. R., Rubin, J., Kvols, L. K., Sarna, G., Koch, R., Currie, V. E., Young, C. W., Jones, S. E.,& Davignon, J. P. (1982). A clinical trial of amygdalin

          (Laetrile) in the treatment of human cancer, New England Journal of Medicine, 306(4), 201-206.


Scheck, A. C., Perry, K., Hank, N. C., & Clark, W. D. (2006). Anticancer activity of extracts derived from the mature roots of Scutellaria baicalensis on human malignant brain

          tumor cells. BMC Complementary and Alternative Medicine, 6, 1-9.


Small, E. J., Frohlich, M. W., Bok, R., Shinohara, K., Grossfield, G., Rozenblat, Z., Kelly, W. K., Corry, M., & Reese, D. M. (2000). Prospective trial of the herbal supplement

          PC-SPES in patients with progressive prostate cancer. Journal of Clinical Oncology, 18(21), 3595-3603.


Spaulding-Albright, N. (1997). A review of some herbal and related products commonly used in cancer patients. Journal of the American dietetic Association, 97 (10), 2-15.


Vickers, A. (2002). Botanical Medicines for the Treatment of Cancer: Rationale, Overview of Current Data, and Methodological Considerations for Phase I and II Trials.

          Cancer Investigation, 20, 1069-1079.


Vickers, A., & Zollman, C. (1999). ABC of complementary medicine: herbal medicine. British Medical Journal, 319, 1050- 1053.












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