Sea water occupies an odd place in traditional practice: revered, used, and genuinely dangerous if misunderstood.
The reasonable part is the mineral content. Sea water carries magnesium, potassium, calcium and a long list of trace elements in roughly the proportions found in body fluids — an observation associated with the French biologist René Quinton, who in the early 1900s used sterile diluted sea water in clinical work and wrote extensively about the resemblance between sea water and blood plasma.
The critical word in that account is diluted. Quinton's preparations were heavily diluted with spring water and sterilised. Full-strength sea water is roughly four times as salty as body fluid. Drinking it does not hydrate you; it dehydrates you, because your kidneys must draw on body water to excrete the excess salt. This is why shipwreck survival guidance is emphatic that you do not drink sea water, and why doing so accelerates rather than delays collapse.
Traditional uses that are sound and low-risk are external: bathing, saline nasal rinses made up to the correct strength, and gargling. Sea bathing is genuinely good for skin, for breathing and for the mind.
Do not drink undiluted sea water. If you have high blood pressure, kidney disease or heart failure, do not take additional salt in any form without your doctor's guidance.
This site is a personal account and a record of traditional practice, shared for information. It is not medical advice, not a diagnosis, and not a treatment for any disease. I am not a doctor.
If you are unwell — and especially if you have a serious illness such as cancer, diabetes or heart disease — please stay under the care of a qualified physician. Nothing here should replace or delay that care.