You can mix liquid medicine into a spoonful of food, too, but solid food may not mask the taste as well as another liquid will. (babycenter.com)
Many parents don't realize that some infant drops are more concentrated than liquid medicine intended for older children. (babycenter.com)
If you must carry more than 100 ml of liquid medicine you will need approval from your airline, but there should be no problem with this. (holidayextras.co.uk)