This pre-War chem was created by Med-Tek. They were designed to increase memory related functions and speed up other mental processes. These chalky red pills were a popular party drug, widely appreciated for their effect on creativity.
Mentats were sold in both cardboard and tin packagings, the latter a bit more likely to survive the nuclear holocaust. They are, of course, highly addictive.
Notably, Berry Mentats do not have the Perception bonus that normal Mentats bring, despite sharing their appearance.
Notably, Orange Mentats do not have the Intelligence bonus that normal Mentats bring.