According to RXlist.com, elderberry consumption (especially raw) can have the following side effects. Nausea/vomiting (eating raw berries) Weakness Dizziness Numbness Stupor However, it's important to point out that for every article that mentions you can't eat raw elderberries, there are ten comments from those claiming they ate them by the handfuls as children without ill effect. I'm no expert on the topic, but the research I did on the subject was very conflicting. For this reason, I prefer to err on the side of caution and not eat them.