Leukemia is one of cancer forms and it affects human blood. The disease is developed in the bone marrow. When affected, it starts producing white blood cells in uncontrolled quantities and this breaks normal blood circulating and functioning. Scientists name two main forms of leukemia – acute and chronic ones. The first one, acute leukemia, is mostly common for children, but sometimes it can affect long adults. This leukemia type is characterized by fast disease developing. Human bone marrow quickly becomes crowded and stops producing healthy cells, so a patient can die if preventive actions are not taken quickly as affected cells spread on tissues and even organs of a patient. Second leukemia type – chronic – is the most spread among adults. This form is not fast growing as sometimes it takes months or even 2-3 years to develop this type of cancer. Treatment for chronic leukemia is also necessary, but sometimes doctors may decide to postpone it and watch how disease develops. Unfortunately, it’s still unknown why diseases like leukemia appear. The only advice available is to try avoiding harmful habits like smoking and prevent radiation exposure. Leukemia development is hard to notice on early stages as it symptoms are common for many other health problems. Most frequently appear symptoms like overall weakness, frequent infections, headaches, nausea or dizziness. Also person becomes more liable to various infections and gets sick faster. As disease spreads, a patient may feel bone pain, bleeding gums, severe weight loss, swollen tonsils and long lasting symptoms that remind flu. The disease treatment depends on the type of leukemia. Acute leukemia is usually treated with various medicines that are not very efficient in treating the disease itself, but they help to prevent development and future spreading to brain and nervous system. Also chemotherapy is used. If no remission or recovery is noticed, doctors may suggest bone marrow transplantation. There’s no one approach to all patients with acute leukemia, but many cases can be cured. Chronic leukemia doesn’t have such a defined treatment schedule. Usually chemotherapy is applied, also doctor may prescribe injections. In case of chronic leukemia the treatment’s aim is different from acute one as here doctors try to control the disease and so person can live without major health problems.