Asthenia is the most frequent symptom in patients with advanced cancer and is probably what most affects the quality of life of oncology patients since it interferes in their physical and social activity. Treatment in the majority of cases is symptomatic. There is growing interest in the use of psychostimulants for treating asthenia. Methylphenidate and modafinil are two psychostimulants that have already been tested in controlled studies on asthenia of the patient with advanced cancer; they have proved to be efficient, particularly in patients in very advanced stages who are very tired.