Staying hydrated during treatment is essential! Dehydration can be common in people undergoing treatment for cancer, especially in those who are experiencing side effects like nausea, vomiting, and diarrhea. The loss of fluids can quickly lead to dehydration, a condition marked by decreased levels of water in the fluid in the body to allow it to properly function. If left untreated or unrecognized, hospitalization may be needed. Learn how to recognize the symptoms of dehydration.