The health care system in Ukraine is seriously underfunded and does not provide services comparable to those in western countries. In addition many facilities have only limited English speakers, and some have none at all.
For elderly persons or persons with existing health problems, it is advisable to consider not to travel to Ukraine at all due to high risk if being unable to obtain adequate medical care.
Also, some medicines may be very difficult to buy so travelers should take a supply of the medicines they need (check first if they can be legally brought into Ukraine...).
By Ukrainian law, all visitors are required to obtain Ukrainian health insurance upon arrival, but the insurance only covers some basic medical care. Public hospitals and clinics can refuse any treatment without this insurance. Private clinics don't require the mandatory insurance but they will likely ask for payment in advance. Note that some countries (like United Kingdom, but not United States or Canada) have bilateral agreements with Ukraine that waive the requirement to purchase the Ukrainian health insurance.
In general, the best option for travelers to Ukraine is to obtain medical evacuation insurance prior to travel or have access to substantial lines of credit to cover the cost of medical evacuation. Evacuation to a medical facility in western Europe is the best way to secure adequate treatment in an emergency.
All travelers are advised to contact their embassy, in the first instance, for advice on where to get medical help.
It is advised that all travelers use boiled, sterilized or bottled water for drinking, or making ice. Tap water is normally safe for brushing teeth, but using bottled or purified water is recommended.
Generally, Ukraine is a safe country to visit, although street crime remains a serious problem. Particularly foreign visitors may be targets of petty crime and theft as they are perceived wealthier than the locals.
Travelers should use common sense precautions, avoid being alone at night in parks or secluded places, try not to show their valuables, jewelery and blend in as much as possible.
It is also recommended to exercise caution when using credit cards or ATM cards - preferably only at reputable businesses.
Exchanging currency on the street should be avoided as well as you may end up being given old worthless banknotes or being scammed with the exchange rate.
All visitors to Ukraine are required to carry their passport (and visa) at all times.
The most common scam against tourists, particularly in Kiev, is so-called "wallet scam". The scam starts with a person dropping wallet or money on the ground. When you pick up the wallet and return it to that person, he will accuse you of stealing money from it (or he will insist that he'd dropped two wallets etc.). The scam may involve thief's accomplices posing as witnesses or police officers. When you then try to prove your innocence and show your own wallet, the thief steals it and flees (or takes money from it).