Medical oncology is concerned with the prevention, diagnosis and treatment of cancers. The oncologist decides the most appropriate treatment based on the diagnosis. Chemotherapy, hormonal treatments, immunotherapy or targeted cancer therapies are available. The dose, the dosing schedule and the combination of individual agents depend on the patient’s condition and the nature of the disease. Cancer drugs are either administered orally or given as an injection or drip (infusion). Intravenous infusions require either outpatient treatment (lasting a few hours) or hospital treatment (lasting from two to several days). Chemotherapy can cause adverse effects. Research and practice strive to limit these side effects to a minimum.