effectiveness of pre and pro biotics are a bit iffy but prebiotics they say you should take first thing in the morning before eating and probiotices they normally say before or during a meal, some people think during a meal is better as it travels with your food but from memory when I used to take them I am fairly sure the general advice was 20 min before eating is the best time to take them and that is the case for a lot of other medications I have had which are similar in concept to pre and pro biotics.Of course everyone is different so its worth an experiment but if you cant be bothered experimenting I would go for 20min before food. (or as soon as you remember should you forget)