Is it dangerous to ingest epsom salts?

Depends on the dose: Epsom salts are Magnesium Sulfate which is safe for human consumption in limited doses. You may notice on the epsom salt container that it can be used as a laxative, which is the effect of ingesting larger amounts of magnesium sulfate. Ingestion of too much could lead to problems due to the laxative effect, but again a small amount should not be dangerous when used appropriately.

Epsom Salts: Ingestion of excessive epsom salts can lead to significant GI upset. In smaller amounts it is sometimes used as a laxative.