To obtain a visa for treatment (C3M) in South Korea, a medical certificate or an extract from a medical card issued by a Russian medical institution or a Russian doctor should be added to the package of documents..Apostille document is not required..Plus, you need an invitation or a contract with a medical institution in Korea and even a copy of the certificate of registration of a medical institution in Korea..At the same time, if a citizen has already had more than two trips for treatment to South Korea, and this fact is fixed in a contract or an invitation - neither a certificate nor an extract from the medical card is needed..

For other visas (including workers), medical documents are not required.