For me, I had never had to "yodel" from motion sickness. Frequently, after the first dive, I had felt uncomfortable, and queasy, (and I had come close a few times). This also seems to get worse with age. I had always found that ginger before and during a dive trip, or drinking ginger ale/coke on the boat helped tremendously...that is until this weekend, when it hit me, and hit me hard, while in some moderately rough seas. Despite my efforts to stay still, look at the horizon, and not gear up, I ended up sharing my "technicolor" breakfast with the ocean. It seems there is always a fine line of when to gear up so that you are in the water faster, and when not to gear up until the sickness passes.
I dived a second dive, but had to cancel my later dives that day. Even on land, I felt like the last place I wanted to be was on a boat. I got my courage up, and I ended up doing a night dive, ate some ginger and although I felt better, I still could not fully enjoy the experience while aboard the boat. The DM suggested Bonine.
I took one Bonine pill before bed, and woke feeling quite fatigued (but that may have been from the dives and the first day in the tropics the day before, rather than the Bonine). I took another tablet in the morning before the dive. All I can say is that it worked miracles for me. I guess it is like the revelation that deep divers have when they first use trimix and realize how narced they used to be before trimix. I felt great and didn't have any real side effects. No noticeable difference in fatigue or sleepiness. Even after the first dive of the day I didn't feel any queasiness. Bonine really worked wonders, for me. At least for me, it seems that ginger helps alleviate the symptoms of motion sickness, where the Bonine completely prevented any symptoms.