<<Disclaimer: Verify this information before applying it to your situation.>> Here's a quick and easy test you can do at home to see if you might have hypochlorhydria (low stomach acid): http://www.drdebe.com/BAKESODA.htm The Heidelberg capsule test is described here: http://www.healthy.net/library/books/textbook/section2/heidel.pdf A very recent book by Dr. Jonathan V. Wright on low stomach acid looks interesting. I haven't yet gotten a copy to read. It's available at www.bn.com, www.amazon.com, www.bordersbooks.com, etc.: http://www.mevans.com/acid.html