Sodium thiosulfate pentahydrate is widely used in photography as a fixing agent to dissolve unexposed silver halides from photographic films and papers, ensuring image permanence. In medical applications, it serves as an antidote for cyanide poisoning by converting cyanide into a less toxic compound, thiocyanate, which is then excreted by the body. It is also used to treat hypersensitivity reactions to iodinated contrast media or iodine. Additionally, in dermatology, it is employed in the treatment of certain skin conditions, such as calciphylaxis, due to its ability to bind calcium ions. It is also utilized in water treatment to dechlorinate water, making it safe for aquatic life and other sensitive applications. Additionally, it plays a role in analytical chemistry as a titrant in iodometric titrations for determining the concentration of oxidizing agents. Its versatility extends to industrial processes, where it is used in leather tanning and textile bleaching.