I am sensitive to drugs, especially the ones that say "may cause drowsiness". However, I take those kind but have to be careful when and where I take them. Today I was home (thank goodness) and took the MucinexDM, within an hour I was asleep and slept for hours. I have not coughed in all that time so it works great! A warning on the box would be helpful. I would hate to think what would have happened if I had taken it and drove off. I understand that I am more sensitive than most people but I would think that statement on the box would protect you as well.