A case is presented of a 76-yr-old woman with primary biliary cirrhosis and adult polycystic liver disease who developed bone marrow toxicity associated with chronic low-dose colchicine therapy. Two months after starting colchicine therapy (0.6 mg b.i.d. p.o.), the patient developed hematologic toxicity as evidenced by transient but profound granulocytopenia which promptly reversed 4 days after the drug was stopped. Bone marrow examination revealed moderate hypocellularity of all cell lines and striking dysplastic changes in the late myeloid and erythroid series. There was no apparent toxicity involving other organ systems. The patient fully recovered. This case is compared with previous descriptions of colchicine toxicity.