Iodine-131, one of the radioactive substances detected around the nuclear power plant during the current nuclear leak, is a radioactive isotope of iodine that can cause thyroid disease and even cancer when inhaled by humans. In response, the Japanese government has been distributing iodine tablets to residents in the area around the nuclear leak. Recently, there has been a rush to buy iodized salt, which has been sold out in some places. In fact, in the current situation, there is no need to take iodine tablets or wear radiation-protective clothing, and there is no need to buy and hoard iodized salt. There is no need to take iodine tablets for the time being. After a serious accident in a nuclear reactor, a large amount of radioactive substances are released into the atmosphere, of which radioactive iodine accounts for a large share. When cells are exposed to radiation from these radioactive substances, the possibility of lesions increases, and the greatest risk is the development of cancer. Radioactive iodine can affect the population in four main ways: inhalation of contaminated air, consumption of contaminated food and water, skin absorption deposits, and direct exposure to radioactive iodine. Iodine has a habit of “running” into the thyroid gland when it enters the body, and when radioactive iodine is deposited in the thyroid gland, it emits rays with a very short range that can only affect the thyroid gland. By taking iodine tablets, the radioactive iodine can “take over” the thyroid gland before it enters the body, so that there is no “space left” for the radioactive iodine to enter the thyroid gland. Therefore, taking iodine tablets can indeed prevent the harmful effects of iodine-131 on the thyroid gland. However, in the current situation, there is no need to take iodine tablets for the time being. There are two prerequisites for iodine supplementation: firstly, the radioactive material leaked from the nuclear power plant must be iodine-131, and secondly, it is clear that iodine-131 leaked from the nuclear power plant has entered the country or our food chain. According to current information, the leaked radioactive material is mainly iodine-131, but in the absence of a clear entry of iodine-131 into the country, iodine supplementation is not necessary. Casual consumption may lead to iodine overdose and cause diseases such as goiter. Especially in pregnant women, excessive intake of iodine can have a negative effect on the fetus. Taking iodized salt has no preventive effect Although iodized salt also contains iodine, its content is far from that of iodine tablets. One piece of potassium iodide contains 100 mg of iodine, while 1 kg of iodized salt contains only 20 mg to 30 mg of iodine. In other words, it takes about 4 kilograms of iodized salt to equal one iodine tablet. If you really eat this way, even if you eat high blood pressure, you will not be able to prevent the effect of iodine-131 radioactive damage. Moreover, the half-life of iodine-131 is only 8 days, after which half of it disappears, and the iodine-131 that escapes from Japan will disappear completely in a short period of time. In addition, since radiation enters the body through dust or adheres to the body surface, the mask can block radioactive dust from entering the body. However, there is also no need to wear a mask for the time being until further information is released by the authorities about the threat of nuclear radiation.