Benzoates (preservative commonly used in soft drinks) have been banned for consumption in several countries, causing allergies, asthma and skin rashes.

In a research published in the journal "The Lancet" (2007), it is confirmed that this same preservative, sodium benzoate causes symptoms of attention deficit disorder.

Another research on benzoate has identified a little known reaction when mixed with ascorbic acid, or vitamin C. When these two substances come together, a small amount of a toxin called benzene is formed, which is a known carcinogen.