Yes, there are several things you can buy (I've got 5 kids and live here.) I've gone to the Apteka and asked for something to fight lice, but I've taken in my bottle from the last time and asked for something similar. Every apteka is going to have it.
One of the things you can ask for is "Pipi family nowoczesny preparat do zwalczania wszy."
I'm not sure if you know Polish since this is my first visit to this forum...just registered, but you can just ask for something "przeciw wszami" and they will understand you. If you know Polish, then just ask for something. Don't be embarrassed about it. They don't need to know if it is for you or your kid brother or sister.