The treatment method for brown discharge in the cat’s ears is:

1. First, control the cat, carry it to a well-lit place, and remove any residue in the cat’s ears. Dry the water stains.

2. Put 2 to 4 drops of ear cleaning water into the cat's ear canal, then rub it from the base of the ear for tens of seconds and then let go. The cat will shake its ears left and right.

3. Use cotton swabs to clean away the dirt on the cat’s outer auricle. Be careful not to use too much force to avoid damaging the cat’s ear canal. Wipe the wet hair around your ears clean to prevent long-term moisture from breeding bacteria.

The reasons for brown discharge in cat ears are:

1. If there is brown stuff in cat ears, it is most likely ear mites. Cats have a high probability of getting ear mites in their ear canals. Usually there is black solid secretion in the ear canal, and the ear canal is relatively dry. If the ear mites are severe, there will be scabs on the edges of the ears.

2. When ear mites occur, the ear canal will itch, and the cat will scratch its ears. It is recommended to go to the hospital for a microscopic examination to confirm the diagnosis. After diagnosis, use ear mite removal drugs for treatment. Regularly clean the ear canal and apply drugs.

3. Cat ear mites are mainly caused by ear mites parasitic on the surface of the cat’s ear canal skin, secreting black or reddish-brown oily toxic substances, which can cause itching of the cat’s ear canal, and they will scratch it with their claws. Ears, some cats' ears will smell bad.