Your bichon frise's fluffy, cotton-ball appearance has a drawback; any brown discoloration stands out dramatically on her white pouf. Preventing stains on her fur can be as simple as a quick wipe-down, but she might have an illness that only your vet can help you treat.
Eyes
Your bichon frise has adorable round eyes that make you want to cuddle with her immediately, but these round eyes can lead to brown streaks on her face. The shape keeps the tears from gathering in the center to be reabsorbed by the eye. Instead, the tears tend to spill right out of the duct onto your pup's face. This can lead to tear staining under her eyes. Wipe under her eyes with a damp rag several times a day, adding a drop of no-tear puppy shampoo to the cloth if you see a bit of brown appearing. Changing her water to distilled water can also help. Distilled water doesn't contain iron oxide, which can discolor her fur with secreted tears.
Mouth
Even though your pooch isn't much on drooling, her saliva can still be an issue when too much gets on her fur. Using a food-safe ceramic water bowl can reduce the chance of her ingesting any iron oxide from metal bowls, which can cause brown stains when mixed with saliva. Buying dog food that doesn't have dyes can also help. Artificial colors can stain her fur directly, but when she ingests it, more can leak out when she licks her lips and lead to brown staining.
Feet
Your puffball pooch enjoys daily jaunts in the fresh air, but that white fur is like a magnet for dirt. Walking her on paved surfaces can reduce her exposure to dirt, but it might take some of the fun out of her outdoor time. Instead, keep towels and wipes by the door to clean her paws, legs and belly immediately after your walk to keep dirt and mud from leaving stains on her fur.
Check With Your Vet
Brown staining is common in bichon frises and other white-haired breeds, but it's best to check with your vet when you notice fur discoloration. Her tear stains might be completely normal, or they might be a sign of an eye infection or problems with the tear ducts. If she's suffering from allergies, she might lick her lips often and leave brown stains, her eyes might water more than normal or she might lick her paws to relieve itching and stain the fur there. Excess salivation might also be a sign of gum disease or a problem in her tummy.