It is entirely possible to take too many Epsom Salt Baths and overdose on the Epsom Salt Baths.
When you do take too many Epsom Salt Baths it can dehydrate your skin as well as dehydrate the body.
Also the Epsom Salt contains magnesium sulfate which can cause a laxative effect and lead to diarrhea if you take too many Epsom Salt baths or sit in an Epsom Salt bath too long.
When you take an Epsom Salt bath you're generally safe as long as you don't soak in the Epsom Salt bath longer than 30 minutes at a time.
Taking an Epsom Salt Bath also helps relieve constipation due to the laxative effect.