Are there any dangers of taking multivitamin and a magnesium supplement together?

Not at all unless...: Magnesium is safe to take in high doses unless you have kidney failure. Most multivitamins don't have much magnesium & many people will benefit from additional magnesium. Magnesium may cause loose stools, esp. If you take too much or use a poorly absorbed form. Magnesium taurate & glycinate are relatively well-absorbed forms, with mag. Citrate next best.