Any of the crucifers: cabbage in particular was a BIG problem when I was nursing Josie, only did that once!
I'm from a German background, so sauerkraut is huge there!
Might also be a dairy thing. Both mine are VERY VERY farty after cows' milk. (We have rice milk for the one who'll drink it and water+supplements for the one who won't.)
You may also want to try probiotics. If your LO's ever had antibiotics, it's possible the gut flora is unbalanced, like we adults often get the runs from antibiotics because they kill off the good bacteria with the bad, and we NEED them to help us digest food. When Nat was just a week or two old, her farts could clear a room. I was GBS+, so I got the antibiotic IV during labor, so she already had them in her system by the time she first nursed. I had some that were gel capsules, put some on the nipple, and the next day NO MORE FARTS! Now my kids (and I) take probiotics regularly, and/or eat yogurt and other cultured foods with the bacteria in them naturally. I also ferment my own sauerkraut now, made with bacteria like yogurt instead of in vinegar, so I can actually digest the cabbage - it's the ONLY way I can!
