This is a concentrated, fragranced bath product, so the reasonable approach is caution rather than assumption. If your skin is sensitive, try a smaller amount for the first bath, for example one tablespoon in a full tub, and keep the soak short. If any tightness, itching, or irritation appears, rinse off and do not repeat. The product is meant for intact skin; do not use it on damaged or very irritated skin.
Extra caution is sensible for children, during pregnancy, and for anyone who generally reacts to strong scents. For a child's bath, it is safer to skip the product or use only a very small amount with good ventilation. If you are pregnant, are breastfeeding, have a chronic skin condition, or take medication, consult a doctor or specialist before using the product.
Before using the product more regularly, you can do a quick tolerance check: dissolve a little salt in water, pour it over a washcloth placed on your forearm, leave it for a few minutes, then rinse. This is not a substitute for professional advice, but it gives you a simple idea of whether your skin tolerates the product. If you are in any doubt, a plain unscented bath salt is a gentler choice.