This section provides information about the distribution, storage and effect of iodine tablets and about what you should do if a serious incident involving a nuclear power plant occurs.

You can download a PDF document containing all the questions and answers.


After an incident at a nuclear power plant, radioactive iodine (I-131) may be released into the atmosphere and subsequently inhaled, or absorbed into the body from the food chain. It is stored in the thyroid gland, exposes it to radiation from the inside and in this way can damage it. This can lead to thyroid cancer. Children and adolescents are at higher risk of developing thyroid cancer as a result of exposure to radioactive iodine.

The thyroid gland needs the element iodine to function normally. A large amount of iodine is contained in the high-dose iodine tablets distributed by the federal government. When these tablets are taken, the thyroid gland is saturated with normal iodine. As a result, for a certain length of time it is unable to absorb iodine; if an incident occurs at a nuclear power plant, it is also unable to absorb radioactive iodine. Inhaled radioactive iodine is therefore excreted from the body rapidly. This eliminates the risk of radioactive iodine accumulating in the thyroid gland. Radioactive iodine in the thyroid gland can lead to thyroid cancer in the longer term as a result of exposure to radiation.

Side effects are rare and generally harmless. Possible side effects are described in the package leaflet, or you can ask your doctor or pharmacy.

Anyone with thyroid gland problems should ask their doctor what they should do in the event of an incident the next time they have an appointment.

If you take the high-dose iodine tablets without a reason, the likelihood of side effects happening is low and short-lived despite the high dosage of active substance that they contain. If you experience severe or persistent side effects, talk to you doctor to be on the safe side. If the tablets have been taken accidentally by an infant, or if you are pregnant or breastfeeding, or if you are being treated for a thyroid disorder, you should consult the doctor treating you. You should also talk to your doctor if you are one of the people for whom the iodine tablets are not suitable (see the section in the package leaflet headed “When should potassium iodide 65 SERB not be taken?”).

The iodine tablets are only suitable for use if there is an elevated concentration of radioactive iodine, as may be the case if an incident occurs at a nuclear power plant. You are urgently advised against taking the tablets without being instructed to do so by the authorities because long-term use on a prophylactic basis affects the functioning of the thyroid gland.

No. The dosage in potassium iodide 65 SERB tablets is too high for this purpose. There are specific options for preventing iodine deficiency, e.g. iodised salt. Please obtain advice from your doctor or in a pharmacy or drugstore.

No, iodine tablets are of no use against substances such as caesium or strontium. These substances may also be released if an incident occurs at a nuclear power plant. They are absorbed by the body mainly from food. The authorities will direct the population to take appropriate protective measures.

If an incident occurs at a NPP, the National Emergency Operations Centre NEOC operated by the Federal Office for Civil Protection will provide information through the media and through Alertswiss about what measures the population needs to take. Other protective measures may include evacuation from an area (if time permits) or remaining at home or in the basement.