Milk laced with a drug. In the book,
A Clockwork Orange, milkbars would sell milk instead of alcohol so that they could serve minors. The milk would be laced with "
designer drugs." Note that in real life milk is not a very effective delivery system for most
psychoactive drugs.
The Korova milkbar sold
milk-plus, milk plus vellocet or
synthemesc or
drencrom. Moloko Vellocet is what we were drinking. This would sharpen you up and make you ready for a bit of the old ultra-violence.