"Franken Berry Stool" was the name given to the red-colored poo of children who, after enjoying their sweet, seasonal monster cereal, paid the price with a trip to the pediatrician courtesy of their frantic parents.

In 1971, General Mills introduced Count Chocula and Franken Berry, the first two of many monster-themed cereals. These included the short-lived Frute Brute, which may have been a childhood favorite of Quentin Tarantino. The original Franken Berry formula got its red color from FD&C Red #2 and FD&C Red #3.

In 1970, Russian studies of FD&C Red #2 concluded that large doses of the dye were toxic to gonads and embryos, and caused intestinal tumors. The Russian studies were startling, but scientists in the U.S. found the studies’ methodology flawed and the results unreliable. Nonetheless, the information caused shockwaves, leading the FDA to conduct many of its own studies. Unfortunately, these studies were beset with errors and mismanagement—FDA scientists themselves repeatedly referred to one as the “bungled” or “botched” experiment. Public revelations of the many failures around safety testing that were revealed as a result of studying Red #2 increased public panic around the dye. In 1976, folding to public pressure, the FDA banned Red #2. 

Red #2 panic in 1976 turned into hysteria, and resulted in many food manufacturers recalling products that used Red #2. One of the most remembered of the “red scare recalls” may be the discontinuation of red M&M's—even though red M&M's did not use Red #2. Red M&M's were re-introduced in 1987, to the public’s delight, restoring the palette its pre-scare state: Red, orange, green, tan, brown and yellow. In 1995 tan was replaced by blue.

–This story was originally published on April 10, 2010. Minor updates have been made.