Medicines are where it can get interesting. You are allowed more than 100ml, and part filled bottles of more than 100ml, provided they have a proper prescription label from a pharmacy on them. They obviously can end up filling up a 3 litre bag, let alone a 1 litre! Depending on where you are, the muppets can vary from being helpful to downright obnoxious - LHR T5 had been the worst. When the dose is 2.5ml, and exceeding it can lead to fainting, demands to 'taste it' need to be refused. Explaining that a collapse at the top of the escalator and what would happen to people further down just about got through to the muppet - who was not a native English speaker, incidentally.
The TSA seem to be on top of this problem, incidentally.
So if the pharmacy is in Tehran, what then?
Slightly related subject
Does anyone know if there has been a legal challenge in the US to the TSA's 'no fly rule' on the basis that it should need a court order, and is illegal without? I'm surprised the ACLU hasn't gotten into that one.