Zydelig is a medication used to treat certain types of blood cancers, specifically chronic lymphocytic leukemia (CLL) and follicular lymphoma. It works by inhibiting specific proteins that help cancer cells survive and grow, thereby slowing down the progression of the disease. This drug is taken orally and is often prescribed for patients who have already undergone other treatments. Common side effects may include diarrhea, liver problems, and infections. It is important for patients to discuss their medical history with their healthcare provider before starting Zydelig to ensure it is a suitable option for their condition.