Salt pills were issued to American and British soldiers in World War II to prevent heat cramps, heat exhaustion, and fatigue in hot climates. Military doctors understood that heavy sweating drained the body of sodium, and they believed replacing that salt was just as important as replacing water. Every soldier fighting in North Africa, the Pacific islands, or other tropical and desert theaters carried salt tablets as a standard part of their field rations.
Why the Military Prioritized Salt
When you sweat heavily for hours, you lose significant amounts of sodium chloride along with water. WWII-era military physicians observed that soldiers who became salt-deficient suffered muscle cramps, dizziness, nausea, and collapse, even when they were drinking enough water. Medical officers in hot theaters reported that inadequate salt intake “played a significant part in the production of heat casualty” and that supplementing salt not only reduced those casualties but improved soldiers’ overall well-being and work efficiency.
Line officers often grasped the need for salt replacement better than the need for water replacement, according to U.S. Army medical records. This sometimes created an imbalance in the other direction, with units emphasizing salt while underestimating how much water soldiers needed. Both British and American military training for hot environments eventually settled on a combined approach: adequate water, adequate salt, proper sleep, and gradual heat acclimatization over a period of days.
How Salt Tablets Were Packaged and Distributed
Salt tablets weren’t handed out separately. They were built directly into the military’s field ration system. The U.S. Army added salt tablets to the accessory packs included with K-rations and C-rations, the individually packaged meals soldiers carried into combat. A typical K-ration dinner carton contained canned cheese, biscuits, a candy bar, beverage powders, sugar, cigarettes, matches, a can opener, a spoon, and salt tablets, all packed tightly into a single box. The lunch unit similarly bundled chocolate bars, dried fruit, peanuts, chewing gum, cigarettes, water-purification tablets, and salt tablets together in a sealed plastic-film packet.
Twelve complete K-rations were packed into a fiberboard box, then overpacked in a nailed wooden crate for overseas shipment. This meant salt tablets traveled with every meal shipment to every theater of war, making them one of the most widely distributed medical items of the conflict.
Dosage and Field Instructions
The 1943 U.S. Army field manual “First Aid for Soldiers” gave straightforward instructions. For prevention, soldiers were told to add two 10-grain salt tablets to each canteen of drinking water whenever they were sweating heavily or suffering from diarrhea or dysentery. The goal was a very mild salt solution, about 0.1 percent concentration, roughly a quarter teaspoon of salt per quart of water.
If a soldier actually collapsed from heat exhaustion or heat cramps, the treatment was more aggressive: lay him on his back and have him drink three to five canteens of cool salt water over a 12-hour period, using the same ratio of two tablets or a quarter teaspoon per canteen. This was considered first aid that any fellow soldier could administer in the field without a medic present.
The Problem With the Tablets Themselves
The tablets had a real design flaw. Compressed salt didn’t dissolve well. Army medical reports noted that the tablets sometimes passed through a soldier’s entire digestive tract only partially absorbed, meaning the soldier got less sodium than expected. Dissolving them in water first turned out to be far more effective than swallowing them whole, which is why the recommended method shifted toward mixing tablets into canteen water rather than taking them like pills.
Swallowing concentrated salt also caused nausea and stomach irritation. There are accounts of soldiers accidentally taking salt tablets thinking they were something else and immediately spitting them out. On D-Day, one captain discovered too late that he had carried salt tablets into combat instead of his intended supplies. The taste was unmistakable and unpleasant, and taking them on an empty stomach could make an already queasy soldier feel worse. In a conflict where troops were also being given motion sickness pills that caused their own nausea, adding harsh salt tablets to the mix was not always welcome.
What Changed After the War
The underlying science held up: sodium lost through sweat does need to be replaced. But the method evolved significantly. Modern U.S. military guidelines treat water as the primary rehydration tool during training and operations, with electrolytes replaced primarily through meals. Standard military diets, whether in garrison or in the field, contain enough sodium to cover most sweat losses without supplemental tablets.
For prolonged periods of heavy sweating where meals aren’t available, current guidelines acknowledge that sodium and other electrolytes (potassium, calcium, magnesium) can be supplemented. But the WWII approach of handing every soldier compressed salt tablets and telling them to dose their own canteens has been replaced by more balanced hydration strategies. The body’s adaptation to heat also plays a larger role in modern planning. As soldiers acclimatize over roughly one to two weeks, their sweat becomes more dilute, meaning they lose less sodium per hour and need less replacement. WWII-era researchers identified this same process in the 1940s, but field conditions rarely allowed for the gradual acclimatization schedule that would have reduced the need for salt pills in the first place.