Both CBD oil and RSO are made from cannabis, but they have more differences than similarities. RSO is a very thick and viscous, THC-rich cannabis extract. It is highly concentrated and it can be difficult to measure a dose, as it has a texture more similar to tar than an oil. CBD oil made from low-THC cannabis plants, sometimes called hemp plants. These CBD-rich plants are extracted to make CBD oil. This oil is often diluted with carrier oils for easier delivery.