Replied by Ted (Bangkok, Thailand)
Tylenol is poisonous to the cat, so do not give that! The liver of the cat cannot detoxify it. A sea salt 1 tablespoon in 1 cup of water plus a one half capful of hydrogen peroxide 3% mixed together and use this as a bath, applied to the body and head of the cat may help. The hydrogen peroxide can be added 3-6 drops 3% per one half liter of water. Those are some of the possibility.
Another way is to ozonate the room, which will kill off the fungus, which is a common cause of the cat to sneeze. If the room is stuffy or smell like mildew chances are this is what is causing the sneezing cat. A Bo-Beep ammonia floor cleaning, follow as per instruction to use as cleaning of the house and laundering of the bed the cat sleeps in may also help. Laundering requires a peroxide cleaner or a chlorinated cleaner to rid of the mildew.