Abstract
Rubiflavin is a recently discovered antibiotic of unknown structure. Preliminary studies have indicated that it inhibits deoxyribonucleic acid (DNA) metabolism preferentially and that it interacts strongly with DNA in vitro. The finding that it forms free radicals intracellularly and that these may be bound to large molecules points to the possibility that this antibiotic may bring about its lethal action after binding to DNA as a free radical.