If you think that your baby may be sensitive to something in your breast milk, try eliminating dairy products (milk, cheese, yogurt) for a couple of weeks, which is how long it takes for the cow's milk protein to work its way out of your milk.
If that doesn't do the trick, you might take a look at spicy foods, wheat products, nuts, strawberries, cruciferous vegetables (such as cabbage, broccoli, and cauliflower), garlic, caffeine, and alcohol. Stop eating likely offenders for a few days, then introduce them one at a time, waiting to see if your baby reacts to one item before introducing the next. The process may take a while, but if it saves your baby any crying time at all, it's worth it.
[source: babycentre.com]
