Bonjela Cool Mint Gel. From 16 Years Only. Cool mint flavour. Effective pain relief from mouth ulcers. Bonjela Cool is indicated for the relief of pain associated with mouth ulsers, brace, denture and cold sores. Also, it helps to reduce inflamation and helps fight infection. - Prepare and Use: Directions: Check that the cap seal is unbroken before first using the product. Massage approximately one centimetre of gel onto the sore area. This can be repeated after 3 hours. For denture sores: Do not apply directly onto the dentures. Leave at least 30 minutes before replacing the dentures in the mouth