Our initial optimism about Ben's response to insulin was premature. Based on urine tests and behavior, we thought 1 unit of insulin had little effect on Ben, so we called Dr. Weiss on Saturday and asked if Ben's dose should be increased. We were surprised that he only increased the dose by .5 units. From all that we could observe, Ben's response to the 1.5 unit dose was excellent. Ben started to eat and play, and the ketone levels in her urine decreased to "trace." Ben was doing so well over the weekend on 1.5 units of insulin that when the ketone levels in her urine started climbing again on Monday, we thought she needed a higher dose of insulin. Dr. Weiss, however, said it would be dangerous to raise the insulin dose without first doing a series of blood glucose tests. He explained that sometimes insulin brings the glucose down too low; then the glucose swings back up again. He told us that the home urine tests would miss such a swing. So Ben's insulin dose remained at 1.5 units, which we feared was too low. On Tuesday morning, Ben was very ill--dehydrated, weak, and nauseous. We called Dr. Weiss again, thinking Ben had ketoacidosis and needed more insulin,and he said we could bring her in for the glucose series right away instead of waiting for the scheduled appointment on Thursday. We took her in and left her with Dr. Weiss to be rehydrated and to get her glucose levels checked throughout the day. Indeed, Dr. Weiss was right: Ben's glucose at 11:30 was 468. By 2:00 it had dropped to *30* !! By 5:00 it was 148, and Dr. Weiss expected it to continue to go up. Dr. Weiss called this a "Somogyi overswing": insulin causes hypoglycemia and the body responds by releasing glucose from the liver; then the glucose swings to the other extreme. This can be detected by blood tests at the proper intervals; urine tests miss the swing. As a result of the blood tests, Dr. Weiss lowered Ben's insulin to .75 units per day. I guess Ben is unusually sensitive to insulin; last week Dr. Weiss said ferrets usually need between 1 and 5 units per day for control of diabetes. Ben was a little better last night, but she's very sick again this morning. Dr. Weiss expects her to be sick for at least a couple of days. I hope the new insulin dose will keep her blood glucose more stable and eventually bring the disease under control. I hope little Ben still has a few of her nine lives in reserve. (For people who are new to the FML, Dr. Weiss removed a nearly-inoperable tumor from Ben in February, and Ben has been on chemotherapy for 6 months. The cancer went out of remission in early July but seems to be under control again.) We're so glad Dr. Weiss insisted on doing the blood tests before changing Ben's insulin dose. (Boy, were we wrong this time!) He saved her life once again. We're lucky to have a doctor who is so *very* knowledgeable about ferrets. Clare (Ben's *very* worried Mommy) [Posted in FML issue 2040]