A former co-worker of mine is on methylphenidate due to being a shift worker. She had some elevated liver enzymes a few months back when she took too much Tylenol inadvertently, and since I am a nurse she asked me if the Ritalin would harm her liver, which is fine now. (She currently is uninsured). Since I am not a physician, I could only try to look up what information I had on hand, and I really didn't see that it was a particularly hepatotoxic medication, but I am not sure if I have all the correct information. Could you please let me know what the answer is? Thank you. Catherine M.