Brilliant Blue (FCF) with E-number 133 is a well-researched, non-toxic, synthetic and organic blue dye. It is soluble in water but is hardly absorbed into the body. It is also called Blue No. 1. It was originally made from tar but today is made from oil.
For those tablets where Brilliant Blue is included as a colour, less than 1/4 mg is added. It is allowed by the EU in an amount of 10mg/kg body weight. In particularly sensitive individuals, the drug may cause allergy-like symptoms.