To my knowledge,
there is no reason why Castor Oil Packs could be unsafe.
Eliminate from your diet all processed foods, and all concentrated sweeteners (sugar), and increase consumption of water, and unrefined foods.
The only salt consumed should be unrefined Sea Salt , naturally reach in magnesium (magnesium sulfate).
You can also take Magnesium sulfate, 1teaspoon or 1/2 teaspoon a day with water. Or good quality mineral water rich in magnesium.