Non-carcinogenic mineral oil based plasticizers and extender oils are utilized more and more in rubber applications due to health and environmental consciousness as well as due to the expected ban on their use in tire treads in the European Union. The chemistry of most alternatives is sufficiently close to the utilized polymers, and they give fully acceptable mechanical and physical performance. The dynamic performance of a compound extended with a high aromatic oil, however, is more difficult to match with new alternatives. Highly refined naphthenic oils comply with the set health and safety criteria are, considering their chemistry, one of the best alternatives when it comes to compatibility with common polymers. By taking into account certain characteristic features when choosing the plasticizer or extender oil, it is possible to find a safe product that performs in a similar manner as the high aromatic oils used by tradition when it comes to physical, mechanical, and dynamic properties.