Radioactive iodine (RAI) therapy is an effective method used in the treatment of thyroid cancer and certain thyroid gland diseases. However, like all medical treatments, RAI also has potential side effects. These side effects are generally temporary and may include:

* Temporary Thyroid Hormone Imbalance: Temporary fluctuations in thyroid hormone levels (low or high) may be experienced after treatment.
* Mild Radiation-Related Symptoms: Mild and temporary side effects such as nausea, vomiting, and changes in taste perception may occur.
* Salivary Gland Effects: Swelling and pain in the salivary glands, and consequently dry mouth and dry eyes, may be experienced.
* General Fatigue and Weakness: A temporary feeling of fatigue and weakness may occur after treatment.
* Headache: Headache may be experienced due to the treatment.
* Effects on Fertility and Pregnancy: RAI therapy can affect reproductive health and should not be administered during pregnancy. Necessary precautions should be taken before and after treatment.
* Risk of Radiation Exposure: During and after treatment, there may be a low risk of exposure to emitted radiation for people in your immediate vicinity. Therefore, it is important to implement social contact restrictions for a certain period.