A child almost always finds it difficult to take a medicine that he or she does not like. Especially with small children, logical arguments that the medicine will make them healthy again do not help at all. 

Parents keep asking why drug manufacturers can't simply make medicines for children taste better. Children have a different sense of taste to adults. Most medicines contain bitter-tasting active ingredients that cannot be sufficiently compensated for by sweeteners so that children do not notice them. 

As an adult, you have learnt to tolerate and even like different flavours over the course of your life, including bitter flavours. Your sense of taste changes depending on which foods you eat more often and you learn to appreciate flavours that you couldn't stand as a child.

It is also difficult to predict which sweeteners in children's medicines will be accepted by children, as children have different preferences. Children's tastes not only vary individually, but also depend heavily on their cultural background. European children generally like strawberry flavouring, which African children find unpleasant. 

Making a medicine tasty is also almost impossible for the reason that taste perception is subjective and difficult to measure. Not to mention that it makes little sense to make a paediatric medicine tasty so that children don't see it as a sweet and take too much of it.