Tab was basically the first diet soft drink widely available, and many people drank it religiously in the 80's.  It was produced by Coca-Cola, and by the time they developed Diet Coke with NutraSweet, Tab was out.  Tab was made with Saccharin, which had been known to kill rats.  Big rats with very pink tails.  You will still find Tab occasionally, but never fear, it is also now made with NutraSweet.