dry mouth and drowsiness are 2 prominent side effects to be concerned about at depth....the drowsiness does not affect me personally, but the dry mouth definitely does.....it is a miracle drug as far as I'm concerned, the only thing that allows me to enjoy my favorite hobbies of fishing and diving...but as stated above, definitely give it a "dry run" on land to see just how it will affect you personally...on a side note, I've recently discovered Triptone, which is OTC and significantly cheaper than Scopalamine.....Ive used it my last 10 times on a boat and not felt one ounce of queasiness yet and 2 of those days were in very rough conditions, just FYI