Every country has their own categorization of medicines which indicates which ones are allowed to be taken without any documentation, which need a prescription, ones that need more documentation and those that are completely banned.
For motion sickness pills, they are usually allowed. Pretty much any medication that is available over-the-counter at your destination country, will be allowed in.
In Canada, it is easy to purchase Gravol and I have taken those pills with me to easily over 40 different countries without ever having in issue. They have a very mild effect though and so in Brazil I switched to Meclizine Chlorhydrate. The difference is night and day. Although these are not available in Canada, I have taken them there, to the US, to Europe (Portugal & The Czech Republic), to the middle-East, Africa and Asia (11 countries in all). Again, I never had any problems taking these with me to any of these countries.
EDIT: Someone in the comments indicated that Kwells is Scopolamine. This is a highly controlled substance . In Canada and the US, it is only available with a prescription. You will need a doctor to write you a letter explaining that you need this medicine. That will not guarantee it will be allowed in though. I had a similar letter written for another medication but whether it is recognized at any of your destinations is up to them. Generally, if you are carrying a small enough quantity for personal use, theses things do not get noticed.