Red 40 may cause symptoms of hypersensitivity in some people, including swelling around the mouth, and it may also cause hives. The colorant might contain contaminants that may contribute to cancer in humans and could trigger hyperactivity in children. In a handful of studies, Red 40 damaged the DNA of mice, according to the CSPI.Â Many food products contain a mixture of dyes that includes Red 40 and the combined effect is not well-known. Limit your intake of Red 40 and other food dyes. Choose products that contain paprika, beet juice, carotene, red cabbage and turmeric for coloring instead of synthetic dyes.