Products containing Ca, Mg or Zn may interact w/ orally administered antacids, gastric acid suppressive medications, antibiotics (tetracyclines, fluoroquinolones), levodopa, levothyroxine, thyroxine, bisphosphonates, penicillamine, trientine, digitalis, antiviral agents & thiazide diuretics. Do not exclude interaction between ginseng & coumarin-type anticoagulants. May inhibit Ca absorption w/ oxalic acid (found in spinach & rhubarb) & phytic acid (found in fiber-containing whole-grain products).