Is diarrhea unhealthy?

Each night before bedtime I supplement with magnesium in both liquid suspension form and pill form, and invariably it gives me diarrhea the next morning. Sometimes pencil-thick, sometimes mushy, and sometimes (rarely) it comes out liquid. It's very predictable, between 8 and 9 AM each morning. I am careful to make sure I drink enough water to avoid dehydration. There is nothing inconvenient, uncomfortable, or unpleasant about this daily ritual. On the contrary, before I started this regimen, I sometimes suffered constipation and clogged toilets.

If inconvenience and potential dehydration are not problems, is there anything wrong with loose stools that come on suddenly each morning? I can easily avoid the issue by taking less magnesium but I'm wondering if there is any harm is continuing my current ways.