The issues of legal use for both CBD and THC products are changing (it seems regularly). In the United States there is constant battle between federal and state laws. As of this writing, all forms of Marijuana and THC (which are on the controlled substance list) are illegal. While some states have legalized it: for medical purposes (with a Marijuana Medical Card) and 2) for recreational use, it's still a battle between the two government agencies and as stated, still illegal under federal law.
CBD/Hemp oil (that contains zero to minimum THC) you should be able to buy legally.
In some states, legislatures have passed laws that make CBD for medical purposes legal. If you purchase Humulus Oil, you should also have no issues as most Humulus Oil is made from "NON THC" plants.
NOTE: Before using CBD/Hemp or Marijuana products, you should always check with your local laws and if traveling check the laws of the city/state your traveling through. Not all CBD/Hemp oil is made the same, so check out our page regarding this issue.