Rinse your mouth with aloe juice frequently. Put some alum on the canker sores. Repeat this twice a day. It helps to relieve the pain and quickens healing. Apply some baking powder on the sores. It could be used either in the powdered form or in the paste form. It will reduce the amount of bacteria in the mouth, Rinse your mouth several times a day by a mouthwash prepared by mixing one tsp. of baking soda in half cup of warm water, Prepare a mouthwash by putting 5 to 6 drops of Grapefruit seed extract in a glass of water. Rinse your mouth with this at least once in a day. It is an excellent disinfectant, Prepare a mouthwash using three parts of water and one part of hydrogen peroxide. Use this mouthwash twice a day, Onion is another excellent home remedy for canker sores. Apply some raw onions to the sores, Rinse your mouth with plum juice. If the sore is too bad then apply the juice on the sore using a cotton ball, Eat fresh papaya fruit or chew fresh papaya leaves. If fresh papaya leaves or papaya fruits are not available then you can also use papaya tablets, Gargle your mouth with a solution made by mixing 1 tsp soda and 1 pinch of salt in a cup of warm water, Apply tea tree oil to the sores, Rinse your mouth three to four times a day with a solution made by mixing 2 tbsp. salt to 6 ounces of warm water, Apply some powdered Goldenseal powder to the sore or rinse your mouth with a mouthwash prepared by mixing ½ tsp Goldenseal powder to ¼ tsp salt and 1 cup of warm water.