The best rash remedy I've ever found is the
postpartum herb bath my midwife recommended:
Calendula blossoms, lavender, comfrey
root, rose hips
You
can buy all of these in bulk at health food stores. If you buy a couple
of ounces of each it will last a while. Mix the herbs together and
store in a tightly sealed container. The calendula and lavender are
lighter in weight than the comfrey and rose hips, so it will look like
mostly calendula and lavender. Put 1/2 cup of the mixture in a
1/2 gallon jar and add 1/2 gallon of boiling water. Let it steep at
least an hour, or overnight is better. Strain and save the liquid
(discard the herbs). Pour the liquid into a tub of water. This is for a
regular sized bathtub. If you are
using a baby bathtub you could just use a cup or two of the brew. You
can also use the brew undiluted on a washcloth as a warm compress.
There
were times
when my boys had terrible diaper rash and we did this at night and the
rash was totally gone in the morning. I have also used it myself many
times (it is wonderful for sore nipples too.)