Red Kola is a carbonated soft drink made by Barr, the company who make Irn Bru. It is bright red in colour, and has a unique taste, sort of like sherbet. It comes in the same glass bottles as Irn Bru, and has the same warning on the label, i.e. "if spilt, this product may stain." In English, this bit of legalese translates as "if spilt, will change the colour of anything far more effectively than the best fabric dye." It is an excellent hangover cure, and also good to drink after returning from a night of drinking, as it contains lots of sugar and not much else.
Its major ingredients are carbonated water, sugar, citric acid, flavourings, colours and preservatives.