A disease characterized by the uncontrolled proliferation, growth, and replication of cells. The human body has several ways to prevent unwanted cell multiplication and can usually eliminate abnormal cells naturally. However, when an abnormal cell escapes elimination and begins to replicate it becomes a serious threat to the human body. That replicating cancer cell can become destructive to surrounding tissue and may even break the walls of blood vessels to migrate into other parts of the body- this is known as metastasis. There are hundreds of different types of cancer that can produce a variety of problems. In most cases, the cancer severity and nature of symptoms depends on the affected organ as well as surrounding tissues. For instance, a tumor in the lung, also known as a Pancoast tumor, may cause shortness of breath, shoulder pain and may even affect that sympathetic pathway to the eye which results in a unilateral pinpoint pupil and droopy lid. 

Because cancer is a major threat, it is often treated with harsh therapies. Unfortunately, many accepted cancer treatments cause a variety of unpleasant side effects and some may even cause other kinds of cancer. Common side effects of cancer treatment include loss of appetite, nausea, and depression of the immune system. 

Research is ongoing about where marijuana can be used as a cancer treatment and possible cure. However, it is well known that cannabis has been successfully used to bring ease to patients who are undergoing cancer therapy by relieving nausea, promoting appetite, and even acting as a protector for cells against bacteria.