My husband George taught me how to make Borsch, which is a meal that includes Beets, Onions, Carrots, Potatoes and Cabbage. Interestingly, most of these are in my recipes for raw juice. Now, George told me the story of how the Russians beat the German Army by saying, "Go ahead and come to Russia, for winter is coming." Then George told me that the Russian soldiers were eating Borsch and they were so hot from the Mustard and healthy from the Borsch that they, in the winter snow, were in their undershirts, and the Germans were dying from freezing to death.

In the picture below, you can see how I cut up my beets after I wash off the soil that sticks to them with a stiff brush. I work harder on this particular vegetable because it comes in the supermarket very dirty, and your juice will taste like dirt if you don't brush and clean your beets thoroughly. It is wise to wear an aprin, beets are very juicy and your stool may become red in color, do not worry about that.

A Concern to Consider
However, as a warning to pay attention to, Ian McAllister at healthforu.info cautions:

The only problem is the same one as you get with heroic injections of vitamin C. If you eat too much raw beetroot, it can kill the cancer faster than your liver can dispose of the waste products. So if you have a large cancer, start with small quantities of beetroot, and gradually increase them until you start to feel unwell, and then back off the amount (healthforu.info/health/healthfood/Beets-Health-Food.php).

Too many juiced beets can be bad for you, and so taking it easy on the beets but still using it in your therapy once in a while would seem best. The beet is not something to overdue or misuse on your own. Moreover, George Mateljan cautions:

Beets...are among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating beets (whfoods.com/genpage.php? tname=foodspice&dbid=49).

Now, this does not mean beets are always harmful. The best advice is to be smart, study and consult a physician!
     Now, Mateljan adds:

If you start to see red when you increase your consumption of beets, don't be alarmed. You're just experiencing beeturia, or a red or pink color to your urine or stool. No need to panic; the condition is harmless.

Beets and Cancer
In Hungary, Dr Ferenczi in Csoma hospital has been using raw beets to fight cancer since the 1950s.  The Red pigment that gives beets their rich, purple-crimson color is called betacyanin, and this is a very powerful cancer fighting agent. In the book Food Colorants, Carmen Socaciu writes:

Beetroot has been used as a treatment for cancer in Europe for several centuries. The high content of betanin in red beetroot (300 to 600 mg/kg) may be the explanation for the purported cancer chemopreventive effects of beets (CRC Press, 2007, p. 169).

And in an article entitled “Health Benefits of Red Beets”, we read:

Beet root is a traditional treatment used for leukemia. Beet root contain an amino acid betaine which has an anti cancer properties. Red beet therapy, consisting of consumption of approximately two pounds of raw, mashed beets daily, has been favorably reported for cases of leukemia and tumors (includes cancer). Research also shows that beet juice can help inhibit the development of colon and stomach cancer (hubpages.com/hub/Health_Benefits_of_Red_Beets).

Beets are a great source of folate that can protect you against Alzheimer’s, dementia, and high blood pressure.

Beetroot is great for the heart as it contains soluble fibre which can reduce cholesterol. It also contains the phytochemicals carotenoids and flavonoids which help prevent LDL ‘ bad’ cholesterol from being oxidised and deposited in the arteries. Plus, it gets converted into sugars very slowly which helps to keep blood sugar levels stable.

People whose diets supplied them with the highest average intake of choline (found in egg yolk and soybeans), and its metabolite betaine (found naturally in vegetables such as beets and spinach), have levels of inflammatory markers at least 20% lower than subjects with the lowest average intakes, report Greek researchers in the American Journal of Clinical Nutrition (Detopoulou P, Panagiotakos DB, et al.)

Preparing Beets
Moreover, it is good to throw away the top and tail. I use one full bunch or they now come in individual beets, which is as you would purchase it in the store. I usually buy ones that will fit into the juicer feeder but you can cut it as I show above and there usually are different size beets, and that is usually enough for one container of juice. Use one small beet if juicing for one glass.

When you finish juicing, your container may not be full, and you then can add store bought apple juice or juice some apples but without the core if you want to thin the juice or fill up your container. This drink is so powerful. Each day it tastes better. If your making juice just for yourself, still fill the container and use it for three days. I would not use it longer than three days, but afterwards, throw any left over juice away and make fresh juice.