A saying meaning that very important things sometimes require a sacrifice or result in casualties. Just as eggs must be broken to make an omelet, sometimes people must suffer for the greater good.

Care should be taken, however, not to equate the breaking of eggs as a guarantee of an omelet. As Prof. Charles P. Issawi said:

One cannot make an omelet without breaking eggs...
but it is amazing how many eggs one can break
without making a decent omelet.