Originally, "yogurt throwing" was a means of protest against authority by Greek youngsters in the late 1950s. They were called "Teddy Boys", a name borrowed from the homonymous British subculture. You see, food throwing was traditionally a form of protest (preferable rotten eggs or tomatoes) but it was only in 1950s when the plastic cup substituted yogurt's classic ceramic pot, a marketing move that made yogurt a non-lethal weapon. The trend of yogurt-throwing was fiercely fought by the authorities with the legendary "Law 4000/1958″ according to which offenders were arrested, had their heads shaved and paraded through the streets of Athens.

...

The law was withdrawn in 1983, by Andreas Papandreou. In 1997, a builder who was member of the Communist Party of Greece (KKE) threw a yogurt on the then Minister of Employment, Miltiadis Papaioannou (now Minister of Justice) and his then Deputy Minister Christos Protopappas (now PASOK's Parliamentary Group Representative) . The court decided that yogurt throwing was not an offense that had to be tried automatically but only if a lawsuit is filed by the victim.

...

According to an article of Eleftherotypia newspaper, written by Georgia Linardou, in 2011 two members of the government and one MP have been attacked with yogurts. Last March, the vice president of the government Theodoros Pangalos was attacked while having dinner at a town just outside Athens. Some months later, Minister of Interior Haris Kastanidis was attacked in a similar fashion while watching "Midnight in Paris" at a cinema in Thessaloniki. Liana Kanelli, an MP with the Communist Party of Greece, has also been attacked with yogurt in June 2011, while she was trying to get through a block of protesters in order to reach the Parliament for the vote on the Mid-Term Program.