Cinnabar mentioned! I think there is symbolism here. Cinnabar is a bright red mineral that contains mercury, which makes it toxic. Despite its toxicity cinnabar has historically been valued for its use as a red pigment. It was the primary pigment in red paints known as vermillion. And in traditional Chinese medicine, it's been used to treat a number of conditions- which can be overused and cause poisoning due to its toxic nature.
So the symbolism is clear- beautiful, but deadly! Healthy in small doses, but deadly if over used!