Is Tylenol safe

Tylenol is particularly hard on your liver. The maximum daily dosage is 4 grams, which is still under debate at present (for being too high a dosage). As far as safety goes, you should be asking your doctor this question. One can read the directions on the box, and follow what they say, and the assumption is that you will be "safe" (no negative health effects), but if you take anything, any pill, any drug, even a vitamin, for months straight, there is going to be some kind of effect on your health, be it harmful or otherwise. Personally, I would not take Tylenol every day for a week, much less for months at a time.