Cases of marijuana allergies exist. In fact, there has been a growing number of people reporting the condition in the past years. Allergic reactions triggered by marijuana can cause symptoms that range from mild to severe. People are also reporting negative reactions when using cannabidiol or CBD oil, according to Medical News Today . “The more people that are exposed to marijuana, the more likely we are to see allergies,” Gordon Sussman, an allergist and immunologist, told CTV News.