My mother is an herbalist/nutritionist and this is what she recommends for colic:
Seed Tea - make from fennel, caraway, anise, or dill seed.
1 Tblsp seeds/8 oz. water
Steep covered for 10 minutes
Add 3 oz. vegetable glycerine. Bottle it.
Dose: 14/ tp 1/2 tsp every 30 minutes if colicky or 15 min. before feeding.
Mother can drink catnip, cinnamon, dill, fennel or lemon balm tea (before nursing). Weak teas could be given to baby by dropperful every 15 minutes.
Personally, if it's only gas, I use chamomile tea - make it weak and give it to my son in a dropper - about 1/2 teaspoon full - and that seems to do the trick. Peppermint is really the best for gas, but it's usually too strong for babies. You might try spearmint - not quite as strong - and just water it down a bit. The advantage with chamomile is that it also makes the baby sleepy!
Hope this helps. God bless.