Prevention of mouth ulcer

Brush your teeth with disinfecting baking soda. Use soft toothbrushes. Do brush hard. Change toothbrush regularly.

Undertake stress management techniques.

Eat 4 tbsp live-culture yogurt a day; it contains bacteria that can keep your system healthy.

Avoid foods that are spicy, salty, or acidic.

Take vitamin and mineral supplements C, B complex, folic acid, iron, and zinc.

Many people have reported excellent relief with a mouth rinse of aqueous colloidal silver; it has a natural antimicrobial effect and boosts immunity. Use after brushing the teeth to help prevent any type of oral infection, including parasites and candida.

If you don't want to get canker sores, there is an easy preventative ,When you feel one starting, just get a 1/2 gal. of orange juice & drink it up in 2 or 3 days-presto it goes away! Lack of vitamin C cause's them you can also take the vitamin-C pills.