The federal Food and Drug Administration yesterday warned the cannabis industry about claiming its products can cure cancer.

While the FDA specifically took aim at four companies (none of them Oregon-based) that it says have made specific claims about their products' efficacy in fighting cancer, such claims are everywhere on the internet.

"In recent years, evidence has also shown that cannabis can be effective in fighting cancer itself," reads a January blog post from the Portland cannabis retailer Pure+Green.

But the feds say such claims are unsubstantiated and potentially harmful.

"Substances that contain components of marijuana will be treated like any other products that make unproven claims to shrink cancer tumors. We don't let companies market products that deliberately prey on sick people with baseless claims that their substance can shrink or cure cancer and we're not going to look the other way on enforcing these principles when it comes to marijuana-containing products," said FDA Commissioner Scott Gottlieb, M.D. in a statement. "There are a growing number of effective therapies for many cancers. When people are allowed to illegally market agents that deliver no established benefit they may steer patients away from products that have proven, anti-tumor effects that could extend lives."