Penicillamine has therapeutic utility as an antidote for copper and lead toxicity and is used in the treatment of Wilson’s disease and cystinuria and as an adjunct in the treatment of rheumatoid arthritis. Mechanistically, penicillamine chelates with a number of heavy metals to form stable, soluble complexes that are excreted in urine. In rats, penicillamine given either by oral gavage or fed in the diet during organogenesis or throughout gestation produced malformations, reduced fetal body weight, and increased resorptions in the range of 360 to 1000 mg/kg or 0.8% and higher in several studies. Developmental toxicity in the human is largely manifested as congenital malformation of the connective tissue of the skin. Penicillamine is a hydrophilic chemical of relatively small size. It is of average polarity as compared to the other chemicals, and it can participate in donor/acceptor hydrogen bonding interactions.