It is reported on a 63-year-old female patient who fell ill 20 years after an echinococcus cyst of the liver with a multiple parasite-caused cyst-formation in the lung which was detected by chance and was already calcified at that time. On account of inoperability a conservative treatment with mebendazole (2,000 md/die, for 4 months). During a one-year follow-up period a drastic involution of the lung cysts with improvement of the general condition of the patient appeared. The affection of the liver, however, remained uninfluenced. The ELISA on echinococcus was unchanged strongly positive also after one year.