We've used Bonine for our children. They have it in a chewable at Walmart. I only give it to them (and use it myself) as needed. The last two cruises we've had really smooth seas and I only needed two pills for a seven day cruise, two kids didn't need any (they're the two that can ride any ride at an amusement park, including the upside down rollercoasters), and one kid needed two. I've found they work pretty quick. Another thing that I've found helps is getting out on deck into the fresh air and drinking gingerale. Good luck!