In general, crushing a tablet into powder and mixing it with foods or beverages is fine, unless directions specifically say not to or it is an extended-release, timed-release, or enteric coated pill. Of course, if directions say to take the tablet on an empty stomach, don't mix the crushed tablet with anything other than water.
Supplements which are sometimes available in extended or timed-release formulas (and, therefore, should not be crushed) include certain multivitamins
, B vitamins
, red yeast rice
, and melatonin
. Some probiotic
supplements are enerically-coated.
If you do crush a tablet to mix with food or a beverage, remember to consume all of the food or drink, in order to get the complete serving of your supplement -- and consume it right away.