Hi Paul, Good old Arm & Hammer is fine for internal &  external use.Many 
folks use it in place of Tums for the tummy. ( They just  haven't found out 
about the "Apple Cider" cure for Gerd , acid reflux etc, yet  )   _Apple Cider 
Vinegar Cures / Earth  Clinic_ 
(http://www.earthclinic.com/Remedies/acvinegar.html#ACIDREFLUX_50555)    Also 
used in cooking---. It is Great  ! when 
used with Epsom Salts as a  detox bath...( _How to Take a Detox Bath: 10  
steps - wikiHow_ (http://www.wikihow.com/Take-a-Detox-Bath)      Our family  
has 
used Arm & Hammer for years. You can get it just about anywhere you can  
buy baking products.. { also great mixed with water to take the corrosion off  
your battery terminals on your vehicles..}  :-)   Lois    _Apple  Cider 
Vinegar Cures / Earth Clinic_ 
(http://www.earthclinic.com/Remedies/acvinegar.html#ACIDREFLUX_50555)