Used as an antidote for cyanide poisoning, administered intravenously to convert cyanide into less toxic thiocyanate. Employed in water treatment to neutralize chlorine and chloramines in aquariums, swimming pools, and wastewater. Commonly used in photography as a fixing agent to dissolve unexposed silver halides from photographic film and paper. Utilized in analytical chemistry for iodometric titrations, where it reacts with iodine to determine concentration of oxidizing agents. Applied in medicine to treat calciphylaxis in patients with end-stage renal disease, helping to reduce calcium buildup in tissues. Used in textile industry for bleaching and dechlorinating processes to stabilize fabrics after treatment. Acts as a sulfur source in some agricultural and biological applications, supporting plant and microbial growth under controlled conditions.