Ahem, my dog suffers slightly with flatulence, for want of a better word. Somebody told me that charcoal biscuits were quite good, but I've not noticed much of a difference.

Does anybody have any other helpful hints for this problem?

You don't say what type of dog this is. A 1/2 teaspoon of baking soda mixed in with their daily food will help. Raising the dog bowls will help if he is taller. That did wonders for my dobie.