Don't worry. Rock salt will not harm your child but make sure he should not eat rock salt in excess amount.
He will become very thirsty. Do not block his access to water or to the toilet.
After a brief consultation with Dr. G, I must emphatically disagree with Alex W.
Sodium levels are tightly controlled in a healthy individual by regulation of urine concentration and production and regulation of the thirst response. In patients with an intact thirst response, hypernatremia (defined as a serum sodium level >145 mEq/L) is a rare entity. When hypernatremia does occur, it is associated with a high mortality rate (>50% in most studies).
In general, hypernatremia can be caused by derangement of the thirst response or the behavioral response thereto (primarily in infants, psychiatric patients, and elderly patients who are institutionalized), by problems with the renal concentrating mechanism (diabetes insipidus [DI]) secondary to kidney pathology (nephrogenic DI) or difficulty with the neurohormonal control of this concentrating mechanism (central DI), or by losses of free water from other sources.
Well, I think rock salt is not really dangerous. All you have to do is to let your child drink a lot of water. If the child felt something wrong then you have to consult your doctor.
Rock salt is not harmless, though it is in excess. He might be hungry for water so give me water in excess as it will pass out through urine. But as the child age is less and eating more amount of rock salt can be dangerous. You should keep an eye on the baby that next time he should not do the same mistake.
Rock salt is harmless, unless it ate 1sack of rock salt, it will just dissolved in the system.
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