There is no doubt that shark cartilage can provide relief to painful, swollen joints, and this is likely due to the mucopolysaccharides. It can also prevent the undesirable growth of new blood vessels into the cartilage and appears to help to regulate the immune system. These are also two of the reasons why it is believed by some to be an effective treatment for cancer by preventing metastasis.
They are valid, and it is metastsis rather than the original cancer that ferquently leads to death. Metastsis is the spread of the disease round the body by the bloodstream, and shark cartilage appears to be able to help to prevent that. It also prevents the growth of blood cells into cancerous areas to feed the cancers with oxygen and other nutrients.
Although there are few reported side effects of shark cartilage, in the interest of safety it is advised that children and pregnant women should avoid it. The same is true of people recovering from recent surgery since it could slow healing due to its effect on repairing blood vessels. If you have a low white blood cell count, do not have a shark cartilage enema since it can cause a potentially fatal infection.