If the medicine is distributed in a syringe i always aim it as far back into my sons throat as possible, this kinda bypasses the tastebuds so he doesnt realise it tastes bad. or you could try hiding it in a little chocolate milk or something that you know she will gobble down. she may not even mind the taste just the fact that she has to take medicine! 3 year olds are notorious for being independent so she may not want to do something she is being made to do, that she didnt decide to do herself! maybe making it seem like it is her idea to take it may make her WANT to take it! Anyway, good luck and also, your pharmacy has flavor they can add that will make it taste better, which i am sure you already know!
Shane