The most common applications of mercury are in the production of industrial chemical drugs and in electronic or electrical products. Mercury is also used in thermometers, especially those for measuring high temperatures. More and more gaseous mercury is still used in the manufacture of fluorescent lamps. In addition, the uses of mercury also include: it can decompose gold from its minerals, so chemicalbooks are often used in gold mines. It was once used to treat sexually transmitted diseases such as syphilis in history, but has long been phased out due to its excessive toxic and side effects. Other uses: mercury switches, pesticides, as mercury cathodes in the production of chlorine and sodium hydroxide, preservatives, as electrodes, batteries and catalysts in some electrolytic equipment.