The answer to 'flea odor' is that a flea odor is typically caused by the presence of fleas in your home. Fleas have a distinctive musty, sweet odor that can be noticeable, especially in areas where they are concentrated. The odor comes from the flea's digestive system and the feces they leave behind.
If you notice a flea odor, it's likely that you have an active flea infestation in your home. This can be a frustrating problem, as fleas can be difficult to eliminate. In some cases, the odor may persist even after the fleas have been removed, as the flea feces and debris can continue to emit the distinctive scent.