Of course excessive amounts of sodium can be toxic. The recommended total daily intake of salt is 4 grams. Those who eat plenty of processed food(ie. most typical Americans) get too much salt, but many on this forum who eat mostly natural foods and tend to avoid restaurant food and canned food, may be sodium deficient. I noticed that I feel better when I increase my salt intake. I now try to remember to add salt to my food. I went for a long time without adding any salt to my food. Those who are mercury toxic probably have a greater than normal need for salt. Some studies of those with CFS(which some believe is really mercury poisoning) have shown that people have had improvements with increased salt intake. Of course those with high blood pressure shouldn't increase their sodium intake. Traditionally those who tend to retain water were told to limit salt intake, however a salt deficiency or an excess of salt can both lead to water retention.