Magnesium salicylate is available both as a prescription and over-the-counter medicine. The maximum daily dosage for adults is 4.8 grams per day. If you have a prescription form of the drug, take it exactly as directed by your doctor. If you take an over-the-counter brand of this drug, follow the directions and warnings on the label. In either case, never take more than prescribed or recommended on the label and never exceed the maximum daily dosage. This is essential advice as too much of this drug can lead to stomach irritation, bleeding problems and even overdose.