People that get cancer usually take medicines, called “chemotherapy”, that often made them feel very tired and sick. These problems can last for many months, even after they are completely cured. In our laboratory we demonstrated that animals that take chemotherapy lose weight and are weaker. As of now, we do not know how to prevent this, in particular because we do not know the causes. For this reason, we want to learn why patients with cancer show the signs of fatigue, so that we can also find new medications to improve their health and help them feel better. Very recently, we discovered that the medications used to kill cancer also destroy the “mitochondria”, that are the little engines in the cells, in our muscles. Because of this, we think that if we can prevent the mitochondria from being lost then we can also help the patients feel better and less tired. We plan to give mice with cancer the regular medications, with or without a new drug, called MitoQ. We think MitoQ will protect the mitochondria in the muscle of mice, will prevent them from losing weight and will make them feel stronger. If we our idea is correct, in the future we will propose the use of MitoQ also in people with cancer. By doing so, the patients will feel better, will have fewer troubles due to the chemotherapy and will also have a better chance to get completely cured and go back to a normal life.