INDIANAPOLIS (AP) — Indiana Attorney General Curtis Hill says a marijuana-derived oil that’s used as medicine for treating people with epilepsy is illegal in Indiana with one limited exception.

Hill released an advisory opinion Tuesday that says substances containing cannabidiol, or CBD, are illegal to possess, make and sell in Indiana under both state and federal law.

The sole exception is that CBD products can be used by people with epilepsy who have joined a new state registry.

But Hill’s advisory opinion leaves unclear how patients on that registry would be able to obtain CBD since it would be illegal to sell it in Indiana.

When Gov. Eric Holcomb signed legislation into law in April that created that new registry he said the legislation was about “empathy” for certain epilepsy patients.