How can you cure cold sores and mouth ulcers that show up every 3-4 months?

Acyclovir: If you get aphthous ulcers (cold or canker sores) frequently then the prescription medicine Acyclovir could help. But you usually have to get it going before you see a sore....Like at the first inkling.

No cure: Treatment of cold sores are with antivirals. Aphthous ulcers take time. L-lysine can treat these and taken regularly can help prent recurrences. Stress is usual cause - emotional, environmental and chemical (citrus, acidic etc). Stresss reduction, exercise and healthy, bland diet, and laughter can help speed healing. If persistent or recurretnt see your primary physician for further eval.