DL-Penicillamine is primarily used in the treatment of Wilson's disease, a genetic disorder that causes copper to accumulate in the body. It works by binding to excess copper and promoting its excretion through urine, thereby reducing copper levels and preventing organ damage. Additionally, it is employed in the management of cystinuria, where it helps decrease the formation of cystine stones in the kidneys by forming a soluble complex with cystine. In rheumatoid arthritis, DL-Penicillamine is used as a disease-modifying antirheumatic drug (DMARD) to reduce inflammation and slow joint damage, although its use has declined due to the availability of newer therapies. It is also occasionally used in cases of heavy metal poisoning, such as lead or mercury, due to its chelating properties. However, its use requires careful monitoring due to potential side effects, including bone marrow suppression and kidney or liver dysfunction.