Mastitis is a burden to both people and animals and this is how I have dealt with it naturally. I had severe swelling and pain in my breast that would not go away. I also had been on an antibiotic that did not help clear my infection, so I decided to try something else. I had already used a very similar version of this for chest colds in our home, so after reading that onions could possibly help, I whipped it up and in a matter of hours the pain was gone. I also made it into a salve for our milk cow which combined with peppermint helped us keep her clear from mastitis also. First I chopped an onion and sautéed it in liquid cooking oil, Safflower or Olive Oil. Once transparent, stop cooking. Let sit and cool a minute. While still warm, not hot enough to burn, but warm I wrapped in cheese cloth and placed on breast in bra. I stuck to chest with tape. Within about 30 minutes my pain was gone. I did leave on about two more hours to make sure all goodness was at work and absorbed. I had no more pain, redness, swelling after that. Bam! It was gone. So then I just had to try on our cow.
Now for Betsy our milk cow, who seemed to be getting mastitis lightly on and off around this same time. We had tried using utter injections of antibiotics. They did work, but we couldn't drink the milk for 5 days and I wondered if this couldn't be somehow causing her to become antibiotic resistant because it seemed the mastitis would return soon. So I cooked up some onions, chopped and sautéed again. This time about 2 or 3 and in more Safflower or Olive Oil so I would be able to have a good amount to use. I again cooked until onions were transparent and let sit until cool, and this time strained them from the oil. I added a little peppermint and basil essential oil to the onion oil. Only a few drops of each are enough, don't over do. Both of these are stimulating oils and will help the utter get things flowing. They are both very high in antibacterial and anti-viral properties. Peppermint will burn if you use too much so I made sure it wasn't. Then to make a salve or "utter balm" I melted the same amount of bee's wax pellets as onion/peppermint oil. I then added 2 Tablespoons of Coconut Oil to the wax and onion oil to help it to spread softly onto utters or into hands. Poured all into a jar and kept in milking stall. We then used this as our milking balm instead of the other stuff bought over the counter. It kept her clear and no more antibiotic injections were needed. I do remember her getting mastitis about 2 more times after I made it, but it would be when Husband was milking and he didn't like the minty feeling of the homemade stuff, so my daughter or I would just go back to using the homemade onion/peppermint balm and give a 'good massage' to her utter and it would clear back up no problem. This is just my own experience and now will use my onion/peppermint balm only for milking!