I have successfully treated conjunctivitis both for me and also my dogs by using a mixture of dried marigold/calendula and eyebright. You can get the dried herbs from a herbalist or health food store. Use 1 teaspoon of the dried herb mixture in 1 cup of boiling water and leave to infuse for 15mins. Strain, then use in a separate eye bath for each eye. For pets dab the eyes with cotton wool soaked in the infusion. Repeat this three times a day or as required until it clears. It is very soothing. In addition I would also recommend to take Echinacea or anything to boost the immune system.