Boilies are hard-boiled baits that were originally introduced to carp angling in the UK during the late Seventies with the sole purpose of keeping 'nuisance' fish from eating away the bait being presented to the Carp… though there were a few forward-thinking anglers back in the sixties that began to experiment with different paste type baits and boiling the ingredients to make them hard.

The baits or ‘boilies’ as they were later to become known were very simple baits originally made from eggs and whole-wheat flour or semolina with some flavoring thrown in for good measure. These baits were rolled into various size balls and then boiled for a while to form a tough skin on the outside of the bait. Carp anglers started catching larger fish on these baits and the word soon began to spread throughout the carp angling community.

In the late seventies/early eighties additional ingredients were added such as sweeteners and preservatives, these baits then started to be manufactured commercially. Both fishery owners and anglers alike found that their catch rate of larger fish seemed to increase. It was also noticed that the fish were gaining weight at a far greater rate than before the introduction of these new baits.

More Info: americancarpsociety.com