Chlorella is single-cell green algae that grows wild in fresh water, and it has long attracted attention as a health food. Chlorella has been on Earth since the birth of the planet owing to its astonishing vitality. The existence of Chlorella was recognized around the time when the first microscope was invented. The Dutch scientist, Beijerinck, discovered Chlorella about 120 years ago. The name Chlorella is taken from the Greek "chloros" meaning green and Latin "ella" meaning small.