White onion or Allium cepa (sweet onion) are a cultivar of dry onion which have a distinct light and mild flavour profile. Much like red onions, they have a high sugar and low sulphur content, and thus have a relatively short shelf life.These onions are slightly sweeter, a bit milder in taste than yellow onions. They're a good choice for dicing and serving raw on sandwiches and salads or in fresh salsas.