This is unlikely to be a problem here because the Portuguese authorities are careful in checking qualifications before allowing medical practitioners to practice here.
A potential bigger problem is checking whether that qualification is current.
In recent years practitioners are required to undergo continuous education and training (CET) in order to keep up with the rapidly changing facets of medicine.
Whilst this is an excelllent idea in practice, it is sometimes difficult for the ex-pat to accrue enough points without returning to their country of qualification and this could create a situation where they have been qualified but are not current and are therefore not legally supposed to operate.
If you are in doubt ask for their registration number ( in UK, G.M.C., G.D.C., G.O.C. ) and contact that body to check currency.
In my case for example my General Optical Council no. is 01-7242 and my qualification currently runs to 31st March 2006.
I do not know however a system for checking whether your doctor, dentist,optometrist is HIV +
