D-penicillamine is a medication primarily used to treat conditions like Wilson's disease, a genetic disorder that leads to copper accumulation in the body. It works by binding to copper and facilitating its excretion through urine, helping to reduce toxicity. Additionally, D-penicillamine is used in the management of rheumatoid arthritis and certain types of kidney stones. It can also help remove heavy metals from the body, such as lead and mercury. However, it may cause side effects, so monitoring by a healthcare professional is essential during treatment.