Elisa, Hi, there are two herbal remedies that are effective against fungus incuding ring worm. One is Black Walnut and the other is Tea Tree Oil. Both can be toxic in large dosage so they must be used topically only. I would strongly caution using them on the breast especially repeatedly or if there is a chance of ingestion by the baby. However the extract and the oil may be applied to the affected area and then covered with clothing. They usually work quickly, one or two drops one each eruption is all that is needed. I do not believe enough can be absorbed through the skin to cause a toxicity problem. If you need more info please ask. Rita