Preparing your own oral rehydration salts requires mixing salt and water in the correct ratio to ensure safety and effectiveness. The commonly recommended ratio is: * 1 Litre of water (about 1000 ml) * 2 tablespoons of salt (about 20-25 grams) However, the World Health Organization (WHO) recommends a low-concentration oral rehydration salt formula: * 1 Litre (1000 ml) of water * 2.6 grams of salt (about 1/2 teaspoon) * 1.5 grams of sodium bicarbonate (optional, but not required) If you don't have sodium bicarbonate or don't want to add it, you can just use water and salt. Following the WHO formula, it can help maintain the balance of electrolytes in the body and relieve symptoms of dehydration caused by diarrhea and other reasons. Remember to use clean water and consult a medical professional if necessary. Please note that if oral rehydration salts are not prepared in the correct ratio, it may cause negative effects or adverse reactions. Therefore, it is best to double-check the formula before preparing it yourself and seek medical attention in time if you feel unwell.