A 2 1/4 year-old boy was treated for cystinuria and urolithiasis with high fluid intake, sodium bicarbonate, and D-penicillamine, over a period of 5 3/4 years, unauthorized interruptions and prescribed pauses included. Therapy was partially sucessful but regrowth of calculi coincided with interruptions of D-penicillamine administration and also with the institution of a low-dose D-penicillamine regime. Flat feet, scoliosis, pectus carinatum, hypermobility of joints, molluscoid pseudotumors and atrophic scars were alarming side effects of D-penicillamine. However, the possibility was not excluded that a forme fruste of an Ehlers-Danlos syndrome preexisted in this boy and was effected by D-penicillamine. Only the molluscoid pseudotumors regressed when D-penicillamine was reduced or omitted temporarily. Osteolathyrism caused by D-penicillamine has hitherto not been reported in man.