Travellers to Lithuania need to arrange comprehensive travel insurance before visiting the country, because there is no reciprocal healthcare agreement between the UK and the country in place at present.
Hospital standards away from Vilnius can be poor, and visitors should consider carrying a sterile medical kit including suture needles, syringes and dressings with them as there are often shortages in local hospitals.
It's a good idea to stick to bottled water outside the main towns, and you may want to consult a doctor prior to visiting Croatia in order to check whether you need inoculations for rabies and tick borne encephalitis which are prevalent in forested areas.